Zlatan Ibrahimovic took his opportunity in his first start since joining Milan, who claimed a 2-0 win over Cagliari on Saturday afternoon.
After a scorless opening 45 minutes, Rafael Leao broke the deadlock shortly after the halftime break with his second league goal of the season.
Ibrahimovic rounded off the scoring and victory for Milan just after the hour mark after turning home a cross from Theo Hernandez.
Inter Milan moved one clear of Juventus at the top of the Serie A table after dropping points at the San Siro on Saturday night.
Lauturo Martinez got the off to a fine start after finding the back of the net after just four minutes to take his tally to 10 league goals.
However, the visitors managed to secure the equaliser with 15 minutes remaining in the second half thanks to a strike from Robin Gosens.
The point means Juventus can overtake Inter with a win over AS Roma on Sunday evening.
Napoli's struggles in Serie A continued after falling to a 1-0 loss to Lazio at the Stadio Olimpico on Saturday evening.
Ciro Immobile was the hero for the hosts after netting the game's only goal on 82 minutes.
The victory sees Lazio strengthen their grip on third spot while Napoli find themselves in 10th spot.
