Both sides had an opportunity in the opening five minutes, with plenty of early intent on display, as Eljif Elmas’ shot was routinely saved before Vanja Milinkovic-Savic spread himself to deny Ruben Loftus-Cheek following Strahinja Pavlovic’s attempted bicycle kick.
Gli Azzurri started to get a greater hold on possession, but Massimiliano Allegri’s side had a big chance when Amir Rrahmani’s header fell to Alexis Saelemaekers, although the Belgian blazed his attempt harmlessly over.
Elmas then fired wide from another opportunity at the other end after Mike Maignan had spilt the ball from a corner. Scott McTominay tried to add some finesse to a highly competitive first half with an effort that eventually went marginally wide, before Adrien Rabiot and Christopher Nkunku sent a shot apiece over at the other end.
The opener eventually arrived in the 39th minute when Maignan could only touch Rasmus Hojlund’s squared ball into the path of David Neres, who applied a simple finish.
Maignan ensured Hojlund didn’t score with his own shot before the break, as the Rossoneri goalkeeper got down well to tip it wide.
The Frenchman was brought into action again in the 54th minute, convincingly palming away Rrahmani’s first-time strike before the ball was allowed to bounce menacingly in Napoli’s box, where Juan Jesus got ahead of Pavlovic to clear the danger.
Koni De Winter had struggled to deal with Hojlund’s threat all game, and the Napoli striker held him off again in the 64th minute, allowing him the space to smash a shot in off the far post from a tight angle.
After Fikayo Tomori headed wide as the Rossoneri tried to restore some hope, Youssouf Fofana emerged from the bench and at least hit the target, but headed straight at Milinkovic-Savic.
The battle continued until the very end, with McTominay and Tomori both being booked after a coming together. Still, Napoli had reason to celebrate as they recovered from back-to-back defeats to earn their place in Monday’s Supercoppa Italiana final against Bologna or Inter Milan.
While AC Milan haven’t lost any of their last 14 Serie A outings, this defeat comes two weeks after they were knocked out of the Coppa Italia.
Flashscore Man of the Match: Rasmus Hojlund (Napoli)