During the 2004–05 season, he made 39 appearances and scored 15 goals, as Udinese came in fourth in Serie A and therefore qualified for the UEFA Champions League. That following season, Iaquinta made 34 appearances with 17 goals, including a hat-trick in his first UEFA Champions League group stage match against Panathinaikos. Although he refused to sign a contract extension at the start of the season, on 30 September he agreed terms for a further 3 years.