Real Sociedad Alonso quickly progressed through the
youth ranks and the
reserve team at Real Sociedad (winning the regionalised
fourth tier in his
single season with the latter) and impressed enough to earn a first-team debut at the age of 18. Alonso failed to make another appearance in the season but the following year brought more opportunities. At the beginning of the
2000–01 season,
Javier Clemente sent him to
Segunda División club
Eibar to gain experience. Alonso's father particularly felt the move to the smaller club improved him as a player. Toshack lauded Alonso, stating that the impression he had on the team was exceptional, especially for a player from the youth team. The club cemented its mid-table position in the
2001–02 season, finishing in 13th place. Alonso appeared consistently in
La Liga with 30 appearances over the course of the season and also scored his first league goal, finishing with a season total of three. Real Sociedad's management changed again in the summer of 2002 with the arrival of
Raynald Denoueix, but Alonso kept his place in the first-team on the strength of his past performances. The
2002–03 season was the club's best league performance since the
1981–82 season, in which they won the league. The Basque club finished second, two points behind
Real Madrid, setting a club record for their highest ever points total, and qualifying for the
UEFA Champions League for the first time. Alonso received much praise for his role in the club's success and was given the Best Spanish Player award by Spanish sports magazine
Don Balón. In addition, Alonso significantly contributed to the club's goal tally, scoring 12 goals in all competitions. His performances earned Alonso national repute and
Iñaki Sáez, the coach of the Spain national team, called him up for the
Spain national football team. Alonso made his international debut on 30 April 2003 in a 4–0
friendly win over
Ecuador. Sáez praised Alonso, saying, "He has a fantastic range of accurate passing [and] sees football with an extraordinary clarity." Arteta was ecstatic at the prospect of partnering Alonso in midfield, but his excitement was short-lived. Alonso did not lament the fact that a move to Real Madrid had not materialised. Instead, he concentrated on integrating with the new Spanish contingent at Liverpool under the guidance of former
Valencia manager
Rafael Benítez. The technical Spaniards were Benítez's first signings and he remarked that their emphasis of skill over strength offered the team something different. Alonso made his
Premier League debut against
Bolton Wanderers at the
Reebok Stadium on 29 August 2004. A
Premier League match away against
Fulham displayed more of Alonso's talents. Liverpool were losing 2–0 at
half-time and Benítez brought on Alonso as a
substitute after the break. He revived a deflated Liverpool and the game finished 2–4 to the Merseyside club. Furthermore, Alonso scored his first
goal for the club from a
free-kick to bring Liverpool ahead of the opposition. in the Champions League in July 2005 Alonso continued to provide important goals for the club, scoring his first goal at Anfield against
Arsenal in a 2–1 victory. Alonso was elated at the achievement and felt he was settling in well in England. The Arsenal match marked the return of
Steven Gerrard from injury but Alonso's midfield partnership with the
club captain came to a halt when Alonso suffered his first setback at Liverpool. Alonso's ankle was broken following a tackle from
Frank Lampard in Liverpool's 0–1 home defeat against
Chelsea on 1 January 2005 and the Spaniard was ruled out of action for three months. Alonso made his return to the first-team in the second-leg of the
Champions League quarter-final against
Juventus. Alonso was not at full fitness but, as Steven Gerrard was injured, he played for the full 90 minutes and Liverpool held the score at 0–0 in Italy, defeating the eventual Italian champions 2–1 on aggregate. Kevin McCarra of
The Guardian paid testament to Alonso's skill and dedication to the game, saying, "This marvellously accomplished footballer testified in the
Stadio delle Alpi that technique can overcome a serious physical disadvantage." In the semi-finals against Chelsea, Alonso received a
yellow card in a tense and scrappy 0–0 draw at
Stamford Bridge, making him suspended for the second-leg. Alonso was distraught that he would miss the game and vehemently contested the referee's decision to no avail. Gerrard returned from injury for the second-leg, however, and the captain steered his club to a 1–0 win with the help of a Luis García goal, qualifying for the final against
Milan. Liverpool's fifth-place finish in the Premier League left much to be desired but debut season glory still awaited Alonso in the form of the
Champions League final. The club fell three goals behind Milan but completed a dramatic second-half comeback. Liverpool, trailing 3–2, were awarded a penalty and it was decided that Alonso would take the spot kick. While
Dida, Milan's acclaimed Brazilian goalkeeper, managed to save the penalty Alonso fired the rebound into the roof of the net, bringing the score to 3–3.
Extra-time passed without a goal from either team and Liverpool won 3–2 in the penalty shootout. Alonso was praised for his pivotal influence on the team's comeback and manager Benítez reinforced his importance to the club. Alonso was ecstatic with the win, commenting, "This is the best moment in my professional career." The epic night was also recalled to be the 'Miracle of Istanbul'.
2005–06: FA Cup winner Alonso was ever-present in the first team in the
2005–06 season, largely avoiding injuries that had marred his first season at the club. The summer
transfer window brought
Peter Crouch to Liverpool and the striker's height sparked accusations that the club would change to
long-ball tactics. Crouch denied this, highlighting that Alonso's passing ability, alongside Gerrard, would define Liverpool's style of play. Alonso faced more competition for his place in the form of new arrival
Mohamed Sissoko. However, Steven Gerrard's injuries and Rafael Benítez's favouring of a
4–5–1 formation ensured Alonso's place in the team. Alonso appeared in all of Liverpool's games in the
Champions League but the dominance shown in the previous season had gone as the club were eliminated by
Benfica in the
Round of 16. On 7 January 2006, in an
FA Cup third-round match against
Luton Town, Alonso assisted Liverpool to a 5–3 comeback victory after being down 3–1 early in the second-half. Alonso scored two impressive goals from distance: one from 45 yards, and the other 65 yards from goal; behind the
half-way line. Consequently, Alonso's goals marked a stroke of luck for a Liverpool fan who won £25,000 from a £200 bet on Alonso scoring from within his own-half. Alonso suffered an ankle injury in a 1–3 away victory over
Portsmouth, putting his participation in the
FA Cup final in doubt. However, he recovered sufficiently to start the match against
West Ham United and Gerrard scored Liverpool's third goal, pulling the club level with the opposition. Alonso, still affected by the injury, could not manage the entire 90 minutes and was substituted in the second-half. Liverpool won 3–1 on penalties without his help but Alonso still earned his first FA Cup winners' medal.
2006–2009 playing for Liverpool in April 2007 On 20 September 2006, Alonso scored what the
BBC described as "an outrageous strike" from his own-half in a 2–0 win against
Newcastle United. Andy Hunter of
The Independent described it as "one of the most audacious goals in Anfield's rich 115-year history". Alonso rebutted claims that his 70-yard goal was all down to luck and stated that he took long range shots as part of his training routine. Despite the similarity of the goals struck from inside his own-half, Alonso was in no doubt which was his best. He said, "I think this was better. The Luton goal bounced a few times, this one went quite straight. The Luton one was left-footed – it was different – but I am quite happy to score the goal." It was his first goal for Liverpool since the goal against Luton, making distinct history as the only outfield player in modern professional football history to score two consecutive goals from inside his own-half of the pitch. The 2007–08 season started well for the Spaniard: Gerrard's absence led to Alonso playing in a more advanced position and he scored twice in a 6–0 win against Premier League newcomers
Derby County. The bright beginning was short-lived, however, as a minor injury sustained in a game against Portsmouth became aggravated in training. The metatarsal injury forced him out of training for six weeks but his return to the first-team was rushed and his injury recurred in his first game back. Alonso's determination and passion proved to be his downfall, and he later reflected, "I had been feeling a bit tired around that time because it was only my first game back and the match was very fast. But as a player you don't want to come off, particularly when the team is winning and I stayed on." Alonso returned from injury in December 2007, but over the following months he increasingly faced competition for a place in midfield from
Javier Mascherano and
Lucas. His role in Liverpool's five-man midfield role was assured, however, as Rafael Benítez regarded him as "a top class player", stating that Alonso had the ability to change games and break down the opposition's defence. Alonso made his 100th league appearance for Liverpool on 12 January 2008 in a 1–1 away draw against
Middlesbrough. The 2008 summer transfer window suggested a move away from Merseyside, as Liverpool pursued England international
Gareth Barry to replace Alonso. By the start of the 2008–09 season, neither Alonso or Barry had moved club but the drawn-out transfer saga had left the Spaniard feeling unsettled at Liverpool and unsure of his position in the team. However, the club's fans did much to restore his spirits, supporting him on and off the pitch, and Alonso responded to this, saying: :[The fans] couldn't have done more to show me how they felt... If I went out for lunch or a coffee, there was always someone who would come over and say, 'We'd love you to stay'. I'm just glad that, in the end, nothing came of it [the transfer] because it wasn't something I ever asked for. Despite the events of the summer, Alonso made a confident start to the season and both his peers and the press praised his strength of character, citing his influence as a factor in the club's strong start to the season. Alonso's importance to the team was further underlined when he scored the only goal, through a deflection, in a 0–1 victory against Chelsea, making Liverpool the first away team to win at Stamford Bridge in over four years. Statistical analysis reflected Alonso's good form: on 11 December, figures from
Opta Sports revealed that he was the first Premier League player to complete 1,000 successful passes in the season. His last goal for Liverpool came in their 1–3 away win at
Hull City on 25 April 2009, striking after his free-kick deflected off the Hull wall.
Real Madrid 2009–10 season Alonso completed his £30 million move to
Real Madrid on 5 August 2009. It has been suggested that he never wanted to leave the Anfield club, with his contract existing until at least 2012, and that his departure was due to differences with Benítez. Alonso was given the number 22 jersey in Madrid and played in a holding midfield position. He scored his first goal for his new club on 21 February 2010, a penalty in a 6–2 win against
Villarreal. Unless he was injured or suspended,
Manuel Pellegrini started Alonso in every match of the Champions League and in La Liga in his first season at Real Madrid. In La Liga, he helped the club finish with a club-record 96 points, three points behind winners Barcelona. It was the third time in Alonso's career that he helped his team set a new club record in terms of points gathered, while finishing in second position (he achieved the same feat with Real Sociedad in 2002–03 and with Liverpool in 2008–09). During his first season at Real Madrid, Alonso scored three goals and was considered one of the club's "most consistent" players. Readers of
Marca made Alonso part of its
La Liga team of the season, as their choice
defensive midfielder; the only other Real Madrid player featured was
Cristiano Ronaldo. Alonso received the same accolade from
ESPN Soccernet. He was also a nominee in the
LFP Awards, awards given out by the
Liga de Fútbol Profesional, the Spanish Football league. Alonso was nominated in the Best Midfielder category, alongside
Xavi and
Javi Martínez. Several members of the Spanish press, as well as a number of Real Madrid supporters, gave Alonso a new nickname during the season:
La Barba Roja ("The Red Beard").
2010–14: Champions League victory Alonso's second season at Real Madrid started with the arrival of new manager,
José Mourinho. He was given the number 14 jersey after the departure of vice-captain
Guti. He scored his only goal of the
2010–11 season against
Real Murcia in the
Copa del Rey, and helped the club win the competition for the first time since
1993. Alonso began his third season at Madrid by scoring the second goal in a 2–2 draw against Barcelona in the
2011 Supercopa de España at the
Santiago Bernabéu Stadium. On 21 September 2011, he made his 100th appearance for Real Madrid in a 0–0 draw against
Racing de Santander. Alonso claimed his first league title of his career. On 8 January 2014, Alonso signed a contract extension with Real Madrid, which would have kept him at the club until 2016. On 29 April 2014, Real Madrid defeated
Bayern Munich 4–0 in the second leg of their Champions League semi-final to qualify for the
final after a 5–0 aggregate win. Alonso received a yellow card after a sliding tackle on
Bastian Schweinsteiger in the first-half; as he already had two before the match, this ruled him out of the final. He claimed his second Champions League winners medal as Real defeated
Atlético Madrid 4–1 in extra-time.
Bayern Munich in 2014 On 29 August 2014, Alonso moved to
Bayern Munich on a two-year deal for an undisclosed fee. He made his debut the following day, starting in a 1–1 draw at
Schalke 04. On 27 September 2014, in a 0–2 win against
1. FC Köln, Alonso broke the record for most passes completed in a
Bundesliga game, with 196. He scored his first goal for the club on 18 October 2014, a free-kick in a 6–0 win over
Werder Bremen. In his 100th Champions League appearance, on 17 February 2015, Alonso was sent-off for a second bookable offence in a 0–0 draw against
Shakhtar Donetsk. On 28 April, he was one of four Bayern players, all
FIFA World Cup winners, to miss in a 2–0 penalty shootout defeat to
Borussia Dortmund in the
DFB-Pokal semi-final. He was also the only player to miss as the club lost the shootout at the end of the
2015 DFL-Supercup away to
VfL Wolfsburg, his attempt being saved by goalkeeper
Koen Casteels. Alonso signed a new contract with Bayern on 18 December 2015, keeping him at the club until 2017. On 9 March 2017, Alonso confirmed via
Twitter his retirement from professional football at the end of the 2016–17 season. He and Bayern captain
Philipp Lahm played their final professional game on 20 May, in a 4–1 victory at home to Freiburg in which he assisted the opening goal for
Arjen Robben. He was substituted in the 82nd minute for
Franck Ribéry. ==International career==