Milan beat Napoli by three goals to one in the ninth round matches.
Milan’s score rose to 20 points in the lead alone, two points behind Sassuolo, his closest competitor, while Napoli froze at 14 points in sixth place.
Zlatan Ibrahimovic led the first goal in the 20th minute with a superb header, before coming back to Milan with a second goal in the 54th minute.
Dries Mertens reduced the score in the 63rd minute with the only Napoli goal, before Pacayako was sent off two minutes later for the second card.
Ibrahimovic was discharged in the 79th minute due to an injury, but Jens Haugi managed to clinch the match in the 95th minute.
Ibrahimovic raised his score to 10 goals in eight games in the Italian league, two goals behind Cristiano Ronaldo.