Milan is 18 points back in 11th.
Earlier, last-place Chievo Verona beat Hellas Verona 1-0 with a last-minute goal in a Serie A derby that hadn't been played in 11 years.
Left unmarked inside the area, Slovenian midfielder Dejan Lazarevic scored with a powerful shot in the second minute of added time for his first Serie A goal.
It was Chievo's first match since Eugenio Corini was rehired as coach.
The victory moved Chievo provisionally level with Sampdoria and Catania at the bottom of the table.
Promoted Hellas remained sixth.
