Regarded as one of the best defenders of his generation, he stood out for his leadership and ability in the air throughout his career in spite of his small stature as a centre back.[4] Ayalacaptained Argentina in a record 63 matches.[5] He played in threeFIFA World Cups and made a total of 115 international appearances.
Ayala began his career in his native Argentina, playing forFerro Carril Oeste. After three seasons, he moved toRiver Plate where his good form attracted the attention of clubs in Europe.
Italian sideParma brought the Argentine defender to Europe. However, the club, having already used their quota of three non-EU players, loaned him toNapoli, who purchased 50% of his rights on a co-ownership deal. Ayala was bought byMilan at the end of the1997–98 season and played there for two seasons untilValencia purchased him for£6.25 million.
After signing with Valencia in the summer of 2000, Ayala made 275 appearances during a seven-year spell at the club.[6] On 24 September 2000, Ayala made his debut for Valencia in a 3–0La Liga win overNumancia.[7] He soon established himself as a first choice central defender forLos Che and started alongside compatriotMauricio Pellegrino in the2001 UEFA Champions League final, where Valencia lost 5–4 toBayern Munich after apenalty shootout.[8] He was later namedbest defender for the2000–01 tournament.[9] The following season, Ayala was part of the Valencia team that won the2001–02 La Ligatitle. He scored the opening goal of a 2–0 defeat ofMálaga which secured the championship on 5 May 2002.[10] In 2003–04, Valencia again won theLa Liga title and beatMarseille 2–0 inGothenburg to win theUEFA Cup.[7] During the2004–05 season, injuries kept Ayala from much of the La Liga campaign as well as theUEFA Super Cup victory overPorto. During his time with Valencia, he was widely regarded as one of the finest central defenders in the world and is considered to be one of the club's all-time legends.[7]
In August 2006, Ayala was not offered a new contract by sporting directorAmedeo Carboni. On 7 February 2007, he announced he would join regional rivalsVillarreal at the end of the season, however before having played for Villarreal, he joinedReal Zaragoza on a three-year deal on 14 July 2007.[11] The buy-out clause in his contract with Villarreal was€6 million (£4.8 million) which was paid in full byReal Zaragoza.
On 3 May 2008, Ayala scored his first goal for Real Zaragoza in the 94th minute againstDeportivo de La Coruña to lead Zaragoza to a 1–0 victory.[12] Zaragoza, however, were relegated to theSegunda División. On 22 November 2008, Ayala scored his second goal for Zaragoza, in the 73rd of a 3–0 win overEibar. On 29 February 2009, he scored his third goal coming in the 54th minute againstReal Murcia as Zaragoza won the match 4–1.
In January 2010, Ayala's contract with Zaragoza was terminated by mutual consent.
Ayala made his debut for Argentina on 16 November 1994 againstChile under coachDaniel Passarella.
Ayala played forArgentina U23 at the1996 Summer Olympics, winning the silver medal. He played for Argentina in the1998 FIFA World Cup and was a non-playing squad member in the2002 competition due to a last-minute injury moments before their first match againstNigeria. He was selected as one of the threeoverage players thenArgentina U23 won thegold medal at the2004 Summer Olympics. Ayala played an integral part in the Argentine squad for the2006 World Cup in Germany. He played brilliantly throughout the tournament and was picked as a member of the All Star Team. In the quarter-final againstGermany, he scored a header that gave Argentina the 1–0 lead, although his side lost the penalty shootout after a 1–1 draw, with Ayala's spot kick being saved byJens Lehmann.
On 30 May 2006, In a friendly match againstAngola, Ayala earned his 100th cap for Argentina.[14]
One of the best defenders in Argentina's history, on 7 February 2007 Ayala became the most capped player of the national team (most ascaptain), beating his friendDiego Simeone, in a friendly victory 1–0 againstFrance played in theStade de France in Paris.
On 5 June 2007, in a friendly againstAlgeria, Ayala captained Argentina for a record 58th international, having equalledDiego Maradona's mark of 57 in the 1–1 draw againstSwitzerland inBasel on 2 June.[5]
On 17 July 2007, two days after playing in the2007 Copa América final, which ended in a 3–0 defeat toBrazil, and during which he scored an own goal, Ayala announced his retirement from international football.[15] Ayala stated, "it has nothing to do with what happened in the final of the Copa América."[15]Javier Zanetti took over from him as captain.
On 30 December, Ayala retired from professional football.[16] On 21 December 2011, Ayala was hired as a football coordinator atRacing Club.[17] In September 2013, a new management arrived, and Ayala was released on 19 September 2013.[18]
In December 2013, Ayala was hired as a technical director / sport director forValencia, where he was going to be the responsible for the whole South American area.[19] The role also involved him scouting in that area to find young talents. He left the club in the middle of 2015.[20]
Regarded as one of the best and most accomplished defenders of his generation, Ayala was mainly known for his ability in the air and tenacious tackling, and also stood out for his leadership and consistency throughout his career. A complete defender, he was also noted for his speed, ability on the ball, and passing accuracy as a centre-back.[4][21]