The Rossoneri were ahead within the opening 30 seconds when Davide Calabria broke clear to score from a Theo Hernandez through ball straight from kick off, and Sandro Tonali doubled the lead before half-time.
Victory was sealed late on with a rapid counterattack, allowing Hernandez to turn provider once more and set up Rafael Leao for a fine finish. Atalanta fought back through a Duvan Zapata penalty and Mario Pasalic scored in stoppage time, to set up a nervy finale.
Maignan 6.5; Calabria 7, Kjaer 7, Tomori 6.5, Theo Hernandez 7.5 (’80 Ballo-Toure N/A); Tonali 8 (’80 Bennacer 6), Kessie 6.5; Saelemaekers 6, Brahim Diaz 6 (’74 Junior Messias 6), Leao 7.5 (’90 Pellegri N/A); Rebic 6.5
Player of the match: Sandro Tonali
The young Italian midfielder pulled off a crucial early block to prevent a certain Malinovskyi goal at 1-0, before showing great awareness to rob Freuler of the ball and break clear to drill Milan further ahead. An excellent display from the increasingly influential youngster.