During his second season, he was moved from his natural position as a centre back to a defensive midfield role, due to injuries to players Thiago Motta, Edmílson and Gerard. That year, Barcelona won its 17th league title on 14 May 2005 after a 1–1 tie with Levante. A month after an injury to his left knee, Márquez returned to play against A.C. Milan in the first leg of the 2006 UEFA Champions League semi-final. Barcelona, playing away at the San Siro, won 1–0. On 17 May, Barcelona won the UEFA Champions League after defeating Arsenal 2–1 in the final, with Márquez playing the entire match. He became the first Mexican to play in a Champions League final and the first to win it. Following his participation with Mexico at the 2006 World Cup, Márquez signed a four-year contract extension with Barcelona, with the buy-out clause set at €100 million.