Pablo César Aimar (born 3 November 1979) is an Argentine former professional footballer and current assistant coach of the Argentina national team. He has been considered as one of the most talented and creative attacking midfielders of his generation. Nicknamed "El Payaso" (The Clown) and "El Mago" (The Magician) due his talent, players as Lionel Messi and Andrés Iniesta mentioned Aimar as their childhood idol.
After starting his senior career at River Plate in 1996, Aimar amassed La Liga totals of 215 games and 32 goals over eight seasons with Valencia and Zaragoza from 2001 to 2008, before spending five years in Portugal with Benfica, winning a combined nine major titles with the three teams.
Aimar earned 52 caps for the Argentina senior team over ten years, representing the nation in two FIFA World Cups and two Copa América tournaments, as well as a FIFA Confederations Cup. He reached the final of the 2005 Confederations Cup and the 2007 Copa América with the Argentine national side.
In 2018, Aimar joined the Argentina national team as an assistant coach. During his tenure, the team won the 2021 Copa América, the 2022 Finalissima, the 2022 World Cup, and the 2024 Copa América.
Aimar's football career begun in earnest when he was offered the chance to play for Estudiantes de Río Cuarto by youth coach Alfie Mercado. He trained with the club's academy three times a week and it was there that he was spotted by River Plate who offered the chance to join their own academy. Aimar's father initially prevented him from joining River as he felt he was too young to be playing football, but relented after manager Daniel Passarella personally asked him to allow his son to play. Having turned down the opportunity to attend medical school to pursue a career in football, Aimar made his debut for River on 11 August 1996 against Colón. His first goal for the club came on 20 February 1998 against Rosario Central. Aimar lifted six titles with River between 1996 and 2000, scoring 21 goals and recording 28 assists in 82 league appearances for the club, with his final appearance coming on 17 December 2000 in a 3–2 loss to Lanús.
In January 2001, Spanish La Liga side Valencia signed Aimar from River for a club-record fee of €24 million (£13 million). He made his debut for the club the following month against Manchester United and drew praise from three-time Ballon d'Or winner Johan Cruyff for his performance after the match. The following weekend he scored on his La Liga debut, netting in a 2–0 away win over Las Palmas. Aimar immediately became a key figure in Valencia's midfield under Héctor Cúper and helped the club reach the 2001 UEFA Champions League final, where they lost to Bayern Munich on penalties.
In the season which followed, Cúper left for Internazionale, and was replaced by Rafael Benítez. Aimar appeared in a total of 33 league games and scored 4 goals as Valencia were crowned 2001–02 La Liga champions for the first time in 31 years, ending as the club's third-highest goalscorer across all competitions for the season. The season thereafter, Aimar jointly topped the Champions League assists table alongside Rui Costa of Milan with five assists to his name, this despite Valencia being eliminated at the quarter-final stage. The club endured further disappointment by ending the league season in fifth place.
The club's failures were soon forgotten, however, as Valencia completed a league and UEFA Cup double the following season. Despite making more than 30 appearances for the season and playing an influential role in the club's UEFA Cup triumph, Aimar was sidelined for large parts of the season in what was to set an injury-plagued tone to his career.
Following a breakdown between Benítez and Valencia's sporting director Jesús García Pitarch, the former left his position at the club and was replaced by Italian manager Claudio Ranieri for the 2004–05 season. A combination of injury concerns and tactical changes from the manager saw Aimar struggle under Ranieri and found himself being employed as a substitute more frequently than before. The Italian departed the club in February and was replaced by Antonio López, who in turn was replaced by Quique Sánchez Flores for the following season. Aimar decided to leave the club at the end of the 2005–06 season having amassed over 200 appearances for the club over the course of five-and-a-half seasons.
In the summer of 2006, Aimar joined fellow top flight club Real Zaragoza on a four-year deal for a reported fee of €11 million, with the club describing the deal as the most important signing in the club's history. At Zaragoza, he was reunited with compatriot and former Valencia teammate Roberto Ayala, who himself had joined the club earlier in the month. Aimar made his league debut on 27 August in a 2–3 away loss against Deportivo de La Coruña and went on to make 32 appearances across all competitions, scoring five goals and helping the club to a sixth-place finish in the league. The following season was a disastrous one for Aimar and Zaragoza as the club, fraught with poor performances and financial mismanagement were relegated from La Liga. Zaragoza's relegation saw Aimar bring an end to his time in Aragon, having made 57 appearances during his two-season stay with the club. During his stint with Zaragoza, he obtained dual-Spanish nationality, having lived in the country since 2001.
On 17 July 2008, Aimar signed a four-year contract with Portuguese side Benfica for a fee of €6.5 million. After struggling with injuries initially, he finished the campaign with a string of strong performances and was able to add a Taça da Liga title to his name.
In the 2009–10 season, Aimar was reunited with former River Plate teammate Javier Saviola, who was let go by Real Madrid following his own injury struggles. The two combined as double trequartista to support striker Óscar Cardozo alongside fellow Argentine Ángel Di María on the wing. The quartet formed the Primeira Liga's most dangerous attack, with Benfica scoring 78 goals on their way to a league and cup double.
Aimar had become a fan favourite at the Estádio da Luz but injuries continued to plague him, and his game time reduced in the coming seasons. In spite of this, he helped the club to its third and fourth consecutive Taça da Liga titles. On 6 June 2013, after 179 official appearances, 17 goals and 34 assists, Aimar announced he was leaving Benfica and thanked the club for "five wonderful years".
On 7 August 2013, Tunku Ismail Ibrahim, the president of Malaysian club Johor Darul Ta'zim and also known as the Crown Prince of Johor, confirmed that Aimar had signed a two-year contract with the team. Upon arrival, he became the highest paid player ever to feature in the Malaysia Super League. He made his debut in the league six months after signing, in a 2–0 win against Perak FA. Prior to making his debut, Aimar had previously played at the Larkin Stadium, home of Johor, before with Argentina in the 1997 FIFA World Youth Championship. He ultimately made 8 appearances for the club and scored two goals before a spate of injuries resulted in him being released on 21 April 2014. Aimar did earn a champions medal for his time with JDT, though, as the club went on to lift the 2014 league title at the end of the season.
On 5 January 2015, Aimar returned to River Plate for the club's pre-season training, stating that he would sign with the club only if he could deal with the physical demand after having undergone surgeries to his heel and not having played since leaving Johor Darul Ta’zim in April 2014. On 31 May, he played as substitute in a home win against Rosario Central in the Primera División. Aimar announced his retirement on 14 July 2015 after River Plate coach Marcelo Gallardo informed him that he was not included in the club's squad for the semi-final stage of the Copa Libertadores. Gallardo said Aimar was "suffering" and had struggled with injuries through the pre-season.
On 16 January 2018, Aimar played in a friendly match for his youth club Estudiantes de Río Cuarto. After the match, he announced that he would be joining the squad ahead of the Copa Argentina fixture against Sportivo Belgrano on 23 January, in order to fulfill his wish of making an official appearance for the club where he began and spent eight years.