Aged 16 and ranked 758 in the world, Ahn made her
major debut at the
2008 US Open having been given a
wildcard entry into the
qualifying tournament and winning three matches to reach the
main-draw, where she lost to sixth seed
Dinara Safina. Representing the
Stanford Cardinal women's tennis team, she was 2011
Pac-10 Championships singles champion and would also be ITA National Rookie of the Year and a three-time All-American during her college career spanning from 2010 to 2014. Ahn won her biggest
ITF Circuit titles in 2017, taking two $80,000 level titles – one each in singles and doubles. In April she teamed up with
Quinn Gleason to win the doubles at
Indian Harbour Beach, defeating
Laura Pigossi and
Renata Zarazúa in the final. Ahn then claimed the singles title at the
Tyler Pro Challenge in November, overcoming
Danielle Collins in the championship match. Sandwiched in between these two title triumphs, Ahn also reached her first
WTA Tour quarterfinal as a qualifier at the
Nottingham Open in June, a run which included a win over eighth seed
Naomi Osaka, before ultimately ending in defeat to
Magdaléna Rybáriková. Having won the
United States Tennis Association (USTA) wildcard challenge, she made her maiden main-draw appearance at the
Australian Open in January 2018, losing to
Barbora Strýcová in the first round. Ahn qualified for the
2019 Wimbledon Championships, making her main-draw debut at the grass-court major in a first round defeat to 12th seed
Anastasija Sevastova. She reached her second WTA quarterfinal at the
2019 Silicon Valley Classic, qualifying for the main-draw and then overcoming
Ajla Tomljanović and third seed
Elise Mertens, before losing to fifth seed
Donna Vekić. Eleven years after her only previous appearance in the main-draw at
Flushing Meadows, Ahn won the USTA wildcard challenge to gain a place at the
2019 US Open. She proceeded to have her career-best run at a major, recording straight sets wins over
2004 champion
Svetlana Kuznetsova, qualifier
Anna Kalinskaya and
2017 French Open winner
Jeļena Ostapenko, to make it through to the fourth round, at which point she lost to 25th seed Elise Mertens. Ranked inside the top-100 for the first time at world No. 93, Ahn was awarded a wildcard entry into the
2019 Korea Open and went on to reach the quarterfinals by
double baggeling Timea Bacsinszky and defeating qualifier
Ana Bogdan in a third set tiebreak, before losing in the last eight to second seed
Ekaterina Alexandrova. Ahn gained direct entry into the
2020 French Open, completing appearances at the full-set of majors, although she lost in the first round to three-time champion and sixth seed
Serena Williams in straight sets. At the
2021 Wimbledon Championships, she lost in the final round of qualifying but entered the main-draw as a lucky loser and defeated
Heather Watson, before bowing out against
Sloane Stephens in the second round. Ahn announced her retirement from professional tennis in March 2022 at the age of 29. ==Performance timelines==