Inter Milan retained its Serie A title with three games to spare after second-placed AC Milan put in a weak performance to lose 2-1 at Udinese on Saturday. Inter's triumph, in coach Jose Mourinho's first season in charge, is its fourth straight scudetto and its 17th overall. The champion, which will celebrate its success in Sunday's home match with Siena, holds a seven-point lead with Milan only having two games left. The defeat of its city rival gave Inter President Massimo Moratti an extra reason to party on his 64th birthday. Fans quickly congregated in Milan's central square, Piazza Duomo, to wave flags and celebrate the title while television pictures showed Inter players dancing in their team hotel. Milan captain Paolo Maldini, who retires at the end of the season, had a night to forget on his 900th appearance for the Rossoneri. The 40-year-old pulled down Antonio Floro Flores on 31 minutes to allow Gaetano D'Agostino to fire home a penalty and then failed to clear a corner before Cristian Zapata slammed the ball in at the far post early in the second half. Massimo Ambrosini headed home in stoppage time for Milan, which is not yet assured of an automatic Champions League spot and has question marks hanging over the future of coach Carlo Ancelotti – continually linked in the media with Chelsea. Inter has now joined Milan on 17 Italian titles with Juventus leading the way on 27. In Rome's Stadio Olimpico, Christian Panucci scored an injury time winner as AS Roma beat Catania 4-3 to close in on a Europa League place next season. Inter's style of play was not always pretty but its sheer physical power and the goals of Zlatan Ibrahimovic meant it has lost just three league matches this term.