Mario Balotelli scored for the third game in a row since joining AC Milan to ensure the hosts took all the points against Parma at the San Siro.
An own goal from Gabriel Paletta gave the Rossoneri the lead in the first half before Balotelli netted his fourth goal in just three games for his new club.
Nicola Sansone scored a consolation for Parma deep in stoppage time but there was no time for the visitors to scramble what would have been an ill-deserved second.
The three points lift Milan above city rivals Inter and level on points with third-placed Lazio.
Paletta could have been Parma's hero in the ninth minute when he popped up inside the Milan penalty area and did the hard work in dribbling past two defenders only to drag his shot wide of the far post.
Unfortunately for Parma, Paletta did find the target at the other end in the 39th minute as he turned Kevin-Prince Boateng's cross into his own net.
Milan set about adding to their lead in a one-sided second half.
Boateng's excellent shot just missed the far post as he tried to turn Balotelli's cross home in the 53rd minute.
With 78 minutes gone, Balotelli preserved his record of scoring in every game since arriving from Manchester City as he curled a free-kick over the wall and beyond Nicola Pavarini's reach.
Parma grabbed a consolation with the last kick of the game when Sansone met Jonathan Biabiany's low cross at the far post.