A dominant AC Milan beat Serie A leaders Inter Milan 2-1 on Sunday to blow open the title race with second-placed AS Roma winning 3-0 at Sampdoria.
With two matches left, Inter's lead has been cut to three points after Christian Panucci, David Pizarro and Cicinho netted second-half goals for Roma.
Filippo Inzaghi and Kaka scored for Milan, who move into fourth spot and the final Champions League qualifying place after rivals Fiorentina lost 2-1 at Cagliari.
Julio Cruz blasted in a free kick to pull one back for Inter, who went into the big derby knowing a victory would have meant they retained their title.