Junior career Nishikori played his first junior match in April 2002 at the age of 13 at a grade 1 tournament in Japan. He won the 2004 title at the Riad 21 Tournament in
Rabat, Morocco, and was a boys' singles quarter-finalist at the
2006 Junior French Open; he partnering
Emiliano Massa to win the
boys' doubles title at that tournament. Nishikori won the 2007 Luxilon Cup held at the
2007 Sony Ericsson Open by defeating
Michael McClune. As a junior, he compiled a 73–37 win–loss record in singles and 53–31 in doubles, achieving a combined ranking of No. 7 in the world in July 2006. Junior Grand Slam results – Singles: Australian Open: QF (
2006) French Open: QF (
2006) Wimbledon: 1R (
2005) US Open: 3R (
2005) Junior Grand Slam results – Doubles: Australian Open: SF (
2006) French Open:
W (
2006) Wimbledon: A (-) US Open: 1R (
2005)
2006 Nishikori began the year in March with a wildcard entry to the
Kyoto Challenger tournament in
Kyoto, Japan, where he lost to Australian
Robert Smeets in the round of 32 and just failed to qualify for the doubles tournament. In May, Nishikori qualified for the
ITF Futures event in
Mazatlán, Mexico, where he was victorious in the men's singles.
2007: Turned professional A finalist in two
USTA Pro Circuit events, Nishikori lost to
Donald Young in
Little Rock, Arkansas and
Alex Bogomolov Jr. in
Carson, California. He partnered with Young to win the doubles title at Little Rock. At the Sony Ericsson Open in
Miami, Nishikori paired with triple French Open champion
Gustavo Kuerten, but the two were defeated in the first round. Nishikori served as a hitting partner for
Roger Federer at
Wimbledon. After his
ATP main draw debut in Los Angeles, Nishikori qualified for the
Indianapolis Tennis Championships in July. He beat
Alejandro Falla in the first round to record his first ATP main-draw win. He followed that up with a three-set win over
Michael Berrer, the eliminator of seventh seed
Robby Ginepri, to advance to his first ATP quarterfinal. Although he lost to
Dmitry Tursunov in two sets, Nishikori became the youngest player to reach the quarterfinals at
Indianapolis since
Boris Becker in 1985. Later that month, Nishikori headed to Washington, D.C. for his third career ATP event. He defeated
Teymuraz Gabashvili in the first round before falling to
Julien Benneteau in the second. He qualified for the
China Open in
Beijing, losing in the first round to
Ivan Ljubičić. In October, Nishikori received a wildcard entry to the
AIG Japan Open Tennis Championships in Tokyo, where he lost in the first round to
Zack Fleishman. He participated in the tournament's draw ceremony and was honored with an award from the Tokyo Sports Writers Club. Nishikori finished the year representing Japan at the Asian
Hopman Cup competition in
Bangkok,
Thailand.
2008: First ATP title . Nishikori started the year by reaching the semifinals of the Miami challenger tournament. He then entered the
Delray Beach tournament as a qualifier ranked world No. 244. He gained entrance to the main draw by defeating
Nicolás Todero and
Alex Bogomolov Jr. In the first round, he defeated
Florian Mayer due to a retirement in the second set. In the second round, Nishikori defeated
Amer Delić, another qualifier. In the quarterfinals, he won against
Bobby Reynolds. In the semifinals, he upset
Sam Querrey. In the final, Nishikori upset top seed
James Blake in three sets to become the first Japanese man in nearly 16 years to win an ATP event. Nishikori lost in the first round of the
Miami Masters to the Spanish player
Albert Montañés. He faced James Blake again, this time at the River Oaks International tournament in Houston, Texas in the first round, but Kei lost in two sets. He went out in the third round of the 2008
Queen's Club Championships against
Rafael Nadal in just over two hours. Facing the world No. 2, Nishikori played well in the match and showed promise. His first
Grand Slam appearance at the
2008 Wimbledon Championships on 23 June 2008 ended in a first-round forfeiture to French player
Marc Gicquel. Suffering from an abdominal muscle strain, Nishikori retired after the second set. In August, he entered the
Beijing Olympics on a wildcard. There, he lost in the first round to
Rainer Schüttler of Germany. Nishikori made his debut at the
US Open, defeating 29th seeded
Juan Mónaco in the first round. He cruised to the third round, after downing Croatian
Roko Karanušić. On 30 August 2008, he became the first Japanese player to reach the round of 16 at the US Open in 71 years, when he beat fourth seed
David Ferrer in five sets in what was considered one of the tournament's major upsets. He lost his chance, however, to compete in the quarterfinals when he was beaten by 17th seed
Juan Martín del Potro in straight sets. In the
Japan Open Tennis Championships, he made it to the round of 16, before losing to Frenchman
Richard Gasquet. Nishikori was given a wildcard for the
Stockholm Open, where he made it to his second ATP level semifinal of the year, despite playing with a knee injury. He received a walkover in his quarterfinal match against
Mario Ančić, who had to withdraw due to illness. In the semifinals, he was beaten by fourth seed
Robin Söderling.
2009: Injury season Nishikori made a disappointing start to the season, losing to
Jürgen Melzer in the first round of the Australian Open. On 25 March, Nishikori was named 2008
ATP Newcomer of the Year and became the first Asian player to win the award. He withdrew from the French Open,
Wimbledon, and the
US Open because of an injured right elbow.
2010: French Open debut Nishikori made his comeback after his injury of the previous year. After receiving a wildcard at Delray Beach, he was beaten in the first round by
Benjamin Becker. Kei returned to the Challenger tour later in April with great success, reaching quarterfinals at both Baton Rouge and Tallahassee events, followed by a victory at the Savannah Challenger over
Ryan Sweeting in the final. On 15 May 2010, he won the Sarasota open by defeating
Brian Dabul, in three sets. Nishikori played in his first French Open. He rebounded from two sets down to defeat
Santiago Giraldo of
Colombia in the first round but he lost his second match against
Novak Djokovic. He lost to
Richard Gasquet in the first round of the
2010 Aegon Championships. At Wimbledon, he played second seed
Rafael Nadal in the first round and lost in straight sets. At the US Open, the Japanese No. 1 met
Marin Čilić in the second round. Nishikori ousted the 11th seed in five sets to advance to the third round, his best Grand Slam tournament showing in 2010.
2011: First Masters semifinal, win over World No. 1, Top 25 . Nishikori opened the season in
Chennai, where he upset two-time defending champion
Marin Čilić in the first round, before falling in the quarterfinals to
Janko Tipsarević. In the
2011 Australian Open, Nishikori reached the third round, defeating
Fabio Fognini and
Florian Mayer along the way. His run was ended in the third round by ninth seed
Fernando Verdasco. After the third-round appearance in Melbourne, his ranking rose to No. 70. At the first two
ATP Masters Series events of the year, Nishikori suffered a first-round loss at
Indian Wells and a second-round loss in
Miami. Nishikori then reached his second final at the
2011 U.S. Men's Clay Court Championships. He was defeated by American wildcard
Ryan Sweeting. At
Roland Garros, Nishikori lost in the second round to
Sergiy Stakhovsky. He faced
Lleyton Hewitt in the first round at
Wimbledon, but lost in four sets. Nishikori then retired in his first-round match against
Flavio Cipolla at the
US Open. At the
Shanghai Masters, Nishikori reached his first Masters 1000 semifinal. He defeated
Robin Haase, fourth seed
Jo-Wilfried Tsonga, and
Santiago Giraldo, in the first three rounds. In the quarterfinals, Nishikori upset 12th-seeded
Alexandr Dolgopolov in straight sets. He lost to No. 2
Andy Murray in his first Masters 1000 semifinal. He reached a career-high of world No. 30, breaking the previous Japanese mark of No. 46, set by
Shuzo Matsuoka in July 1992. In the
2011 Swiss Indoors Basel tournament, Nishikori defeated an ailing world No. 1
Novak Djokovic to reach the final, coming back from a 4–5, 0–30 deficit in the second set. The win was only Djokovic's fourth loss of the season, second loss in a completed match, and first loss of a completed match on a non-clay surface. Nishikori was defeated in the final by
Roger Federer. On the heels of the victory, Nishikori was granted special exemption into the
2011 BNP Paribas Masters in Paris, and achieved a ranking of world No. 24.
2012: First Grand Slam quarterfinal and second ATP title Nishikori started the season at the
Brisbane International, where he lost in the second round to
Marcos Baghdatis. At the
2012 Australian Open, Nishikori came back from a set down to defeat sixth seed
Jo-Wilfried Tsonga to reach the quarterfinals of the Australian Open, where he was then defeated by fourth seed
Andy Murray. Nishikori was the first Japanese male player to reach the quarterfinals of the Australian Open in 80 years. Nishikori made it to the quarterfinals of the Hall of Fame Tennis Championships after beating Belgian
Olivier Rochus in three sets. In the
Summer Olympics, Nishikori lost to Argentina's
Juan Martín del Potro in the quarterfinals. He and
Go Soeda lost in the first round of the men's doubles. In Toronto, he lost his first match (after a first-round bye) to
Sam Querrey. He did better in Cincinnati, making it to the third round before being defeated by
Stan Wawrinka, who ended up a semifinalist in the event. Nishikori had also lost to Wawrinka in the quarterfinals in Buenos Aires in February. On 7 October, eighth seed Nishikori won the Rakuten Japan Open in Tokyo against sixth seed
Milos Raonic of Canada in three sets to win his first ATP 500 series title and second career ATP Tour title, lifting his world ranking from world No. 17 to a career-high of world No. 15. Nishikori's win was historic as he became the first Japanese man to win the Japan Open in its 41-year history.
2013: Third ATP title . Nishikori started the year by playing the Brisbane International and reached the semifinals before retiring to Andy Murray because of a knee injury. Nishikori then reached the fourth round of the Australian Open before falling to fourth-seeded David Ferrer. Nishikori was bothered by a nagging knee injury throughout the match. Nishikori then won his third career title in the U.S. National Indoor Championships by defeating Feliciano López in straight sets. Seeded fifth, Nishikori finished the tournament without dropping a set in taking the winner's check, and moved up six ranking spots from No. 22 in the ATP rankings to No. 16. On 9 May, Nishikori defeated defending champion
Roger Federer at the
Madrid Open in the third round, but lost to
Pablo Andújar in the quarters. In the first round of the 2013 US Open, Nishikori lost to a lower-ranked opponent, this time to world No. 179
Dan Evans in straight sets.
2014: Career breakthrough, US Open final Michael Chang became Kei Nishikori's coach in 2014. Nishikori made it to the fourth round in the
Australian Open, but was dismissed by
Rafael Nadal in straight sets. He defended his title at the
U.S. National Indoor Tennis Championships in Memphis, defeating
Ivo Karlović in the final. He then played at the
Masters 1000 event in Miami, where he was seeded 20th. Nishikori saved four match points before defeating 4th seed
David Ferrer and advanced to the semifinals with a three-set win against 5th seed
Roger Federer. Because of a left groin injury, he gave 2nd seed
Novak Djokovic a walkover in the semifinals. He withdrew from Japan's
Davis Cup quarterfinal against the
Czech Republic. Nishikori returned to action at the end of April, in Barcelona, winning the final against
Santiago Giraldo of Colombia in two sets. On 10 May, Nishikori made history by reaching the final of
Madrid Open, his first Masters 1000 tournament final. Nishikori beat
David Ferrer in three sets in the semifinal, and faced world No. 1 and defending champion Rafael Nadal in the final. Nishikori won the first set and led by a break in the second, but Nishikori sustained a back injury while leading 4–2 and was forced to retire at 3–0 in the third set having lost seven games in a row. The result saw him achieve a career-high #9 in ATP singles ranking. Nishikori lost in the first round of the French Open to
Martin Kližan in three sets. Nishikori bounced back from the French Open first round loss in the grass court season by reaching the semifinals of the
2014 Gerry Weber Open before losing to
Roger Federer in straight sets. Nishikori participated in the
Wimbledon Championships and made it to the fourth round after surviving a tight 5-setter against clay-court specialist
Simone Bolelli, but eventually lost in the fourth round to
Milos Raonic, despite winning the opening set. Nishikori opened his hard-court season by participating in the
Citi Open. He reached the quarterfinals only to be beaten by
Richard Gasquet for the fifth time in his career in straight sets. Nishikori reached his first Grand Slam final at the
2014 US Open. He beat
Wayne Odesnik,
Pablo Andújar,
Leonardo Mayer and then world No. 6
Milos Raonic in a marathon five-set match that lasted until 2:26 am, tying the record for late finishes at the US Open en route to the quarterfinals. In the quarterfinals, he scored a rare upset over Australian Open champion
Stan Wawrinka, who had thus far dominated their meetings to ensure that he would regain a top ten ranking. He also became the first Japanese man in 81 years to reach the semifinals at a Major since
Jiro Sato in
1933 French Championships (now French Open). Nishikori then defeated world No. 1
Novak Djokovic in the semifinals to become the first Asian man ever to reach a Grand Slam tournament final. (As reference, an American male tennis player of Asian descent
Michael Chang reached the final of Grand Slam to win
French Open at the youngest age of Grand Slam history, and the finalist to be Runner up in both
US Open and
Australian Open.) In the final, Nishikori lost to
Marin Čilić. Nishikori's run at the US Open saw his singles ranking improve to world No.8. Nishikori began the Asian Swing by entering the Malaysian Open as first seed and won for a third season title, beating
Julien Benneteau in two sets. Nishikori then went on to participate in the Rakuten Japan Open and won the title for the second time defeating
Milos Raonic in the final. However, in the Shanghai Rolex Masters, he later suffered a first round loss to
Jack Sock in straight sets. Nishikori then played in the BNP Paribas Masters and reached the semifinals, defeating
Tommy Robredo,
Jo-Wilfried Tsonga and
David Ferrer, each in three sets. However, he was ousted by
Novak Djokovic in straight sets. This semifinal appearance guaranteed his berth for his
ATP World Tour Finals debut. In his first Year-End
ATP Finals, Nishikori defeated
Andy Murray and
David Ferrer, but was defeated by
Roger Federer in straight sets. With this result, he progressed through to the semifinals and faced
Novak Djokovic, losing in three sets, thus ending the year at a career high world No. 5.
2015: World No. 4, French Open quarterfinal Nishikori began the 2015 season by participating in the
2015 Brisbane International and reached the semifinals before being beaten by
Milos Raonic in three tight-set tiebreaks. He reached the
2015 Brisbane International doubles finals with his partner
Alexandr Dolgopolov but lost in straight sets. Nishikori equalled his best record yet in the
Australian Open by reaching the quarterfinals for the second time in his career, dropping only two sets along the way, but he was beaten in straight sets by defending champion
Stan Wawrinka. In February, Nishikori won his eighth singles title and became the first ever player to win the
Memphis Open three times in a row, beating
Kevin Anderson in straight sets in the final. He next participated in the
2015 Abierto Mexicano Telcel and reached the final, losing only a set to
Kevin Anderson in the semifinals. By reaching the final, he earned enough ATP ranking points to move into a new career high world ranking of No. 4. However, he lost to
David Ferrer in straight sets in the final. During the March Masters, he reached the fourth round of the
2015 BNP Paribas Open for the first time in seven appearances but was upset by
Feliciano López in straight sets in the fourth round. In the
2015 Miami Open, he defeated
Mikhail Youzhny,
Viktor Troicki and
David Goffin all in straight sets losing only a total of 10 games to reach the quarterfinals. However, he was upset by an in-form
John Isner in straight sets. Nishikori began his clay-court season at the
2015 Barcelona Open Banc Sabadell where he reached the final after beating
Teymuraz Gabashvili,
Santiago Giraldo,
Roberto Bautista Agut and
Martin Kližan. He successfully defended his title by beating
Pablo Andújar in the final in two sets to win his ninth career title on the tour. At the
2015 Mutua Madrid Open, Nishikori was granted a first-round bye and proceeded by defeating
David Goffin in three tough-sets in the second round. He reached the semifinals after beating
Roberto Bautista Agut and
David Ferrer in straight sets respectively. He then lost to
Andy Murray in the semifinals, and his ranking dropped to sixth as a result of failing to defend his points from the final in 2014. Nishikori was given a tough draw at the 2015
Italian Open but managed to reach the quarterfinal after beating
Jiří Veselý and
Viktor Troicki, both in straight sets. He faced world No. 1
Novak Djokovic in the QF and lost in three sets. Nishikori opened his French Open campaign by defeating both
Paul-Henri Mathieu and
Thomaz Bellucci in straight sets to advance to the third round. He advanced to the 4R for the second time in his career after his third round opponent,
Benjamin Becker, withdrew due to a right shoulder injury. Nishikori became the first Japanese man to reach the quarterfinals of the French Open in 82 years by beating
Teymuraz Gabashvili. He then played home favorite
Jo-Wilfried Tsonga, but eventually lost in five set. Nishikori opened his grass-court season by participating in the
Halle Open where he reached the semifinals, only to retire in his match against
Andreas Seppi down 1–4 in the first set due to his calf injury which he attained in his quarterfinal match. Nishikori decided to play Wimbledon, and he reached the second round by beating
Simone Bolelli in five sets for the second straight year but then withdrew from his second round match against
Santiago Giraldo, due to his calf injury acting on him again during his first round match. Nishikori opened his hard-court season by competing at the
2015 Citi Open defeating
James Duckworth,
Leonardo Mayer,
Sam Groth, and
Marin Čilić en route to the final where he beat
John Isner in three tight sets to capture his third title of the year and 10th title overall. At the
2015 Rogers Cup, he reached the semifinals without losing a set and defeated
Rafael Nadal for the first time in eight tries in the quarterfinals. He lost to Andy Murray in the semifinals in straight sets. He withdrew from the Cincinnati Masters citing fatigue and hip injury, which affected his semifinal match against Murray the previous week. He lost in the first round of the
2015 US Open to
Benoît Paire. Nishikori started the Asian Fall by participating in his hometown tournament,
Rakuten Japan Open, where he reached the semifinals, including victories over
Borna Ćorić,
Sam Querrey and
Marin Čilić. He was upset in his semifinal match by unseeded Benoît Paire. He reached third rounds of the
Shanghai Rolex Masters before losing to
Kevin Anderson. He then played in the
BNP Paribas Masters. However, he retired in the third round match against
Richard Gasquet due to an abdominal injury. Nishikori qualified for the
ATP World Tour Finals for the second straight year in a row, clinching eighth place. He defeated
Tomáš Berdych, but lost to
Novak Djokovic and
Roger Federer. He failed to qualify for the semifinals, finishing in third place in his group.
2016: Olympic bronze medal Nishikori began the season ranked No. 8. In January, he entered the
Brisbane International as the No. 2 seed where he advanced to the quarterfinals with a bye and a straight sets win over
Mikhail Kukushkin, but was eventually upset by seventh seed
Bernard Tomic in three sets. At the
Australian Open, Nishikori was seeded seventh. He began with victories over
Philipp Kohlschreiber,
Austin Krajicek and
Guillermo García López before beating ninth-seeded
Jo-Wilfried Tsonga to reach his third Australian Open quarterfinal, where he lost to
Novak Djokovic. Nishikori next competed at the
Memphis Open where he was seeded first and was the three-time defending champion. Nishikori received a bye into the second round and advanced to the semifinals without dropping a set. In the semifinals, Nishikori beat
Sam Querrey in three sets and later beat young American
Taylor Fritz in straight sets to win his fourth straight Memphis title and his 11th ATP title overall. He joined
Jimmy Connors as the only four-time winners of the event. During the March Masters, Nishikori reached the quarterfinals in the
Indian Wells Masters for the first time in his career after defeating
Mikhail Kukushkin,
Steve Johnson in straight sets and saving a match point against ninth seed
John Isner in Nishikori's serve in the third set. He lost to fourth seed
Rafael Nadal in straight sets. Nishikori improved his feat by reaching the quarterfinal again in the
Miami Open by beating
Pierre-Hugues Herbert,
Alexandr Dolgopolov and
Roberto Bautista Agut in straight sets. He then reached the semifinals of the tournament for the second time in his career after saving five match points and beating
Gaël Monfils in a comeback three-set match. He then reached his second final in a Masters 1000 after dismantling
Nick Kyrgios in straight sets. He lost to then world No. 1
Novak Djokovic in the final in straight sets. For the fifth consecutive year, Nishikori did not play in Monte Carlo and instead turned his focus to defending his
Barcelona Open Banc Sabadell title. He reached the final without losing a set, but lost in straight sets to resurgent nine-time champion Rafael Nadal in the final. He followed his good run by reaching the semifinals in the
Mutua Madrid Open, beating
Fabio Fognini,
Richard Gasquet for the first time in seven meetings and rising teenage star
Nick Kyrgios. He lost in the semifinal to Novak Djokovic in straight sets despite a close second set. Nishikori then replicated his Madrid run by reaching the semifinals of the
Italian Open for the first time after beating
Viktor Troicki in the opener in three sets, followed by wins over Richard Gasquet and
Dominic Thiem in straight sets. He lost in the semifinal against world Novak Djokovic in a marathon three hours three-setter despite winning the first set 6–2 and managed to pull off a tiebreak in the third set. He later participated at the
French Open but lost to an in-form Gasquet in the fourth round in four sets. Nishikori began his grass season at the
Halle Open, but retired in the second round due to a hip injury. His next tournament was at Wimbledon, where he retired in the fourth round against
Marin Čilić, once again due to injury. With Murray, Federer and Nadal absent, Nishikori was seeded third for the
Rogers Cup Masters in Toronto. After beating
Grigor Dimitrov and
Stan Wawrinka in the quarterfinals and semifinals respectively, Nishikori then lost to Djokovic in straight sets in the finals, going 0–5 so far in the season against the Serb. Nishikori then participated in the
2016 Summer Olympics, where he reached the semis before being defeated by World No. 2
Andy Murray in straight sets. However, he later acquired the bronze medal after he defeated Rafael Nadal 6–2, 6–7 (1), 6–3, becoming the first Japanese man to win an Olympic tennis medal since
Ichiya Kumagae in the
1920 Summer Olympics. He won his first match, upsetting third seed,
Stan Wawrinka in straight sets 6–2, 6–3 before losing his other two
round-robin matches to
Andy Murray and Marin Čilić respectively, both in three sets. Having done enough to nevertheless make the semifinals however, he was then defeated by a resurgent
Novak Djokovic in straight sets, ending his season with a singles ranking of world No. 5 for both the second time in his career and in the past three years as well.
2017: Wrist injury and out of the top 20 Nishikori began the year by reaching the finals of
Brisbane, beating Wawrinka along the way, before falling to champion
Grigor Dimitrov. In the
Australian Open, after defeating
Andrey Kuznetsov in five sets in the first round, Kei beat his next two opponents in straight sets. His run ended in another five-set match to eventual champion
Roger Federer. Nishikori withdrew from the
US Open in
Cincinnati with a right wrist problem and subsequent scans revealed a tear in one of the
tendons. Soon after that, he announced that he would miss the rest of the season. As a result of his extended absence, following the conclusion of
Paris he fell to World No.22, his lowest ranking since January 2012 and his first time out of the top 20 in the rankings since March 2014.
2018: Return from injury & back to top 10 Nishikori returned after a 5-month injury layoff and started his 2018 season by playing at the American challenger tour events. In
Newport Beach he lost in the first round against American qualifier
Dennis Novikov. In the following week, Novikov and Nishikori met again in the first round. This time, Nishikori won in straight sets. Kei Nishikori went on to win his next four matches en route to win his sixth ATP Challenger career titles in
Dallas, by defeating
Mackenzie McDonald in the final. Nishikori made his return to the ATP Tour competition (since August 2017 Montreal) at the inaugural ATP 250 Tournament in
New York. Nishikori made a back-to-back winning return in New York by defeating
Noah Rubin and
Evgeny Donskoy in the first and second round respectively. He defeated
Radu Albot in the quarterfinals in three sets, before losing to
Kevin Anderson in the semifinal. Kei Nishikori was unseeded at the
2018 Abierto Mexicano Telcel in Acapulco and lost against
Denis Shapovalov in the first round. In a bid to regain match fitness, Nishikori entered the
Monte-Carlo Masters for the first time since 2012, having never progressed past the third round at the tournament before. Unseeded for the tournament, he beat
Tomáš Berdych,
Daniil Medvedev,
Andreas Seppi,
Marin Čilić, and
Alexander Zverev to reach his 4th career Masters 1000 finals, before losing to Rafael Nadal in straight sets in the finals. He thus became the active player with the most Masters 1000 finals without a title. At the
2018 Italian Open, he advanced past
Feliciano López, third seed
Grigor Dimitrov, and
Philipp Kohlschreiber before losing to Novak Djokovic in the quarterfinals in three sets. At the
2018 French Open, Nishikori was seeded 19th. He defeated
Maxime Janvier,
Benoît Paire, and
Gilles Simon before falling to seventh seed
Dominic Thiem in the fourth round. In the lead up to Wimbledon, Nishikori lost to
Karen Khachanov in the 2nd round at the
Halle Open. Entering Wimbledon with continued injury woes, expectations were low for Nishikori to make a deep run. He beat
Christian Harrison and
Bernard Tomic before upsetting
Nick Kyrgios in the 3rd round. In the 4th round, despite facing some elbow pain, Nishikori came from a set down to beat
Ernests Gulbis, reaching the quarterfinals of Wimbledon for the first time. Thus, Nishikori had succeeded in reaching the quarterfinals of every grand slam event. In the quarterfinals, he lost to eventual champion
Novak Djokovic in four sets. At the
US Open, Nishikori was seeded 21st. He defeated
Maximilian Marterer in straight sets in the first round, facing
Gaël Monfils in the second. Monfils was forced to retire in the second set after sustaining a wrist injury during the match. Nishikori then defeated 13th seed
Diego Schwartzman and
Philipp Kohlschreiber to reach his third quarterfinal at the US Open. There, he faced
Marin Čilić in a rematch of the
2014 final. He dropped the first set 2–6, but pulled out a close five-set victory, breaking Čilić in the final game of the fifth set to win 6–4. He advanced to the semifinals, losing to
Novak Djokovic in straight sets, 6–3, 6–4, 6–2. Nishikori was the top seed at the
Moselle Open. He defeated
Peter Gojowczyk and
Nikoloz Basilashvili before being upset by qualifier
Matthias Bachinger in the semifinals in three sets. He then participated in the
Japan Open seeded third, defeating compatriot
Yūichi Sugita in the first round,
Benoît Paire in the second, fifth seed
Stefanos Tsitsipas in the quarterfinals, and eighth seed
Richard Gasquet in the semifinals. In the final, he was upset by unseeded
Daniil Medvedev. At the
Shanghai Masters, Nishikori was seeded eighth, defeating
Wu Yibing and
Sam Querrey to reach the quarterfinals, where he was defeated by top seed and defending champion
Roger Federer. At the
Vienna Open, Nishikori was seeded fifth. He defeated
Frances Tiafoe,
Karen Khachanov, top seed
Dominic Thiem, and
Mikhail Kukushkin to reach his third final of the year, where he was defeated by second seed
Kevin Anderson. At the
Paris Masters, Nishikori was seeded tenth. He defeated
Adrian Mannarino before facing
Kevin Anderson in the third round, this time defeating him in straight sets. He was then defeated by third seed
Roger Federer in the quarterfinals. However, by reaching this stage of the tournament, he accrued enough points to secure a spot in the
ATP Finals. At the
ATP Finals, Nishikori was seeded seventh. He was drawn in Group
Lleyton Hewitt and faced second seed
Roger Federer in his first match, defeating him in straight sets. This was Nishikori's first victory over Federer since 2014 and ended a six-match losing streak against him. He was eliminated in the group stage after losing his next two matches against
Kevin Anderson and
Dominic Thiem. He ended the season ranked World No. 9.
2019: First title since 2016 Nishikori started his 2019 season at the
Brisbane International, where he was seeded second. He defeated
Denis Kudla, sixth seed
Grigor Dimitrov, and
Jérémy Chardy to reach the final, where he defeated fourth seed
Daniil Medvedev in three sets to win the title. This was his first tournament victory since February 2016 and broke his streak of nine consecutive final losses. At the
Australian Open, Nishikori was seeded eighth. In the first round, he faced qualifier
Kamil Majchrzak, who was making his Grand Slam main draw debut. Majchrzak took the first two sets in just 90 minutes, before suffering from cramps. Nishikori won 15 of the next 17 games, before Majchrzak retired down 3 games to none in the fifth set. In the second round, he faced
Ivo Karlović, against whom he took the first two sets before dropping the third and fourth. The fifth set proceeded to a tiebreak, which Nishikori won 10–7. In the fourth round, he faced 23rd seed
Pablo Carreño Busta. He dropped the first two sets before staging a major comeback, winning the third and fourth and leading by a break in the fifth before failing to serve out the match. Nishikori narrowly forced a tiebreak, trailing until a crucial point at 8–5, in which Busta contested an incorrect late call. The umpire awarded the point to Nishikori, who proceeded to win the tiebreak 10–8. He thus advanced to his fourth Australian Open quarterfinal, where he retired in the second set against
Novak Djokovic. At
Rotterdam, Nishikori was the top seed. He defeated
Pierre-Hugues Herbert,
Ernests Gulbis and
Márton Fucsovics before he lost in the semifinals to
Stan Wawrinka. At
Dubai, he entered as first seed, defeating
Benoît Paire in the first round before being upset by
Hubert Hurkacz. At
Indian Wells, he was the sixth seed in the singles draw, defeating
Adrian Mannarino before losing again to
Hubert Hurkacz. He also entered the doubles draw, teaming with
Máximo González. They lost to
Raven Klaasen and
Michael Venus in the first round. At the
Miami Open, seeded fifth, he lost his first match to
Dušan Lajović. At the
Monte-Carlo Masters, Nishikori was defending an appearance in the final, but lost to
Pierre-Hugues Herbert in the second round. At
Barcelona, he entered seeded fourth, defeating
Taylor Fritz,
Félix Auger-Aliassime and
Roberto Carballés Baena, being defeated by
Daniil Medvedev in the semifinals. At the
Madrid Masters, he was seeded sixth. He defeated
Hugo Dellien before losing to
Stan Wawrinka in the third round. At
Rome, he entered as sixth seed, defeating
Taylor Fritz and
Jan-Lennard Struff before losing to
Diego Schwartzman in the quarterfinals. At the
French Open, Nishikori was the seventh seed. He defeated
Quentin Halys and
Jo-Wilfried Tsonga before defeating
Laslo Djere and
Benoît Paire in tight five-set matches in the third and fourth rounds, respectively. In the quarterfinals, he was defeated in straight sets by defending champion
Rafael Nadal, who went on to defend his title. At
Wimbledon, Nishikori was seeded eighth. He reached the fourth round without dropping a set, defeating
Thiago Monteiro,
Cameron Norrie, and
Steve Johnson. He dropped a set against
Mikhail Kukushkin in the fourth round, but won the match in four, reaching the quarterfinals at Wimbledon for the second consecutive year. He was defeated in four sets by
Roger Federer. He reached the third round at the
2019 US Open.
2020-2022: Olympics & first top 10 win in 3 years, ATP 500 semifinal, surgery He returned to the Major level, a year later in September 2020, following the COVID season break at the
2020 French Open where he won his first round match. Nishikori started his 2021 season playing in the
2021 ATP Cup, losing both of his singles matches to
Daniil Medvedev and
Diego Schwartzman. At the
Australian Open, Nishikori lost in the first round to
Pablo Carreño Busta in straight sets. Nishikori made his first quarterfinal since
Wimbledon 2019 in
2021 Rotterdam, after beating 7th seed
Félix Auger-Aliassime and
Alex de Minaur. He lost to
Borna Ćorić in two tiebreak sets. He also made the quarterfinals in
2021 Dubai, beating
Reilly Opelka, 5th seed
David Goffin and
Aljaž Bedene. He lost to eventual finalist
Lloyd Harris in three sets. Nishikori was seeded at an event for the first time since the
2019 US Open in
Miami. Seeded 28th, he once again beat Bedene, but lost in the third round in three sets to
Stefanos Tsitsipas. Nishikori's clay-court swing also showed progress of his return. His first tournament was
2021 Barcelona, where after beating
Guido Pella and 13th seed
Cristian Garín, he took a set off
Rafael Nadal before losing in the third round in three sets. Nishikori reached the second round in
Madrid, and the third round in
Rome, losing both matches to
Alexander Zverev. He recorded his best Grand Slam result in over a year at the
French Open, beating
Alessandro Giannessi and 23rd seed
Karen Khachanov in five sets. After his third round opponent,
Henri Laaksonen retired, he progressed to the fourth round, losing once again to Zverev. His 2021 grass court swing was much more quiet, losing in
Halle to
Sebastian Korda and in
Wimbledon to
Jordan Thompson. At the
2020 Tokyo Olympics, Nishikori recorded his first top 10 win since 2018 by beating
Andrey Rublev in straight sets in the first round. He also beat
Marcos Giron and
Ilya Ivashka to reach the quarterfinals, where he lost in straight sets to
Novak Djokovic. Nishikori then participated in
2021 Citi Open in Washington, where he beat
Sam Querrey and 9th seed
Alexander Bublik in straight sets. He then beat
Cameron Norrie to reach the quarterfinals. There, he beat
Lloyd Harris in straight sets to advance to the semifinals. He lost to
Mackenzie McDonald in three sets. He reached the third round at the
2021 US Open. In October, he played his last event of the season at the
2021 BNP Paribas Open where he lost in the second round. On January 25, 2022, Kei Nishikori announced that he will be undergoing
arthroscopic surgery on his left hip and will be aiming to come back on tour in about six months.
2023-2024: First Masters quarterfinal in 5 & ATP final in 6 years Nishikori announced he was aiming to be able to return for the
2023 Australian Open, stating that he has a 'strong desire' to return. However, two weeks before the start of the tournament he announced he is still struggling with an ongoing foot injury and delayed his return to an undisclosed date. In April 2023, after one and a half year of absence, he announced he is planning to make his comeback at a Challenger level in May 2023. In June, after close to two years off the ATP Tour he returned at the Challenger 75
2023 Caribbean Open in Palmas Del Mar, Puerto Rico, and won his first match against American Christian Langmo. He then defeated
Mitchell Krueger,
Adam Walton, and
Gustavo Heide to reach the final, where he defeated another American
Michael Zheng to win the title. He became the only player ever to win an ATP Challenger title while being unranked. He competed in his first tournament since Indian Wells 2021 at the
2023 Atlanta Open where he reached the quarterfinals defeating
Juncheng Shang. He skipped all the ATP Challenger tournaments on home soil in November and December due to a left knee injury. He received a wildcard for the
2024 Miami Open but lost to
Sebastian Ofner. Ranked No. 350, he entered the
2024 French Open using protected ranking and defeated qualifier
Gabriel Diallo in five sets, for his first Major win since the US Open in 2021 and first win at Roland Garros the same year. Ranked No. 576, using protected ranking, he also entered the
2024 National Bank Open and defeated
Alex Michelsen and eight seed
Stefanos Tsitsipas to reach the round of 16. He then defeated
Nuno Borges to reach his first ATP quarterfinal in a year and first Masters quarterfinal in five years since 2019. As a result he moved more than 350 positions back up to world No. 222 on 12 August 2024 and to the top 200 a month later. At his home tournament the
2024 Japan Open Tennis Championships, where he received a wildcard, he reached another quarterfinal defeating
Marin Čilić and
Jordan Thompson, before losing to sixth seed
Holger Rune. He returned to the top 150 two weeks later at world No. 143 on 14 October 2024. In November 2024, Nishikori won his eighth ATP Challenger title at the
HPP Open in
Helsinki, Finland, defeating
Luca Nardi in the final in three sets. As a result he moved up to world No. 107 in the singles rankings on 11 November 2024.
2025: First Asian player with 450 wins, back to top 60 He reached his first ATP Tour final in six years at the
2025 Hong Kong Open after the retirement of
Shang Juncheng and returned to the top 100 in the rankings on 6 January 2025, for the first time since June 2022. He lost the match against
Alexandre Müller in three sets. At the
2025 Australian Open, Nishikori scored his first win at the tournament since 2019 with his 29th five-set career win over
Thiago Monteiro. With another five setter victory in the books, Nishikori record for the second highest winning percentage among active men’s players (after Djokovic) improved to 29-8. In February 2025, Nishikori recorded his 300th hardcourt career win to clinch the
2025 Davis Cup Qualifiers first-round tie for Japan. Nishikori became only the 26th man in the entire
Open Era to achieve the feat and only the second man born in 1989 or later, after
Grigor Dimitrov. At the
2025 Mutua Madrid Open Nishikori recorded his 450th career win over
Aleksandar Vukic, joining as the eight player the list of active players with 450+ wins and becoming the first Asian player to achieve the feat. ==National representation==