Gonzalo Higuain scored twice as Napoli came from behind to beat AC Milan 3-1 and reinforce its bid for a Champions League place after Fiorentina's earlier victory over Atalanta in Serie A on Saturday.
Adel Taarabt took less than eight minutes of his Serie A debut to fire Milan in front, racing half the length of the pitch before curling a wonderful finish into the bottom right corner.
Gokhan Inler levelled three minutes later with a deflected effort.
Higuain, who also had an effort ruled offside, netted twice in the second half to take his season tally to 16 in all competitions.
It was Clarence Seedorf's first league defeat as Milan coach.
Napoli remained three points ahead of Fiorentina, which won 2-0 earlier.
Also, Udinese beat Chievo Verona 3-0 in a relegation battle.