Atalanta have come away from the San Siro with a 1-0 win courtesy of a strike from Luca Cigarini.
It took a while for the game to find a rhythm, but when it did Kevin-Prince Boateng went close with a shot from outside the box after five minutes.
Fouls were interrupting the flow of the game, however the deadlock was nearly broken on 21 minutes when German Denis hit the post.
Milan upped the pressure around the half-hour mark but neither side could find a way through and the half ended 0-0.
The game remained close but it was the visitors who took the lead on 64 minutes, with German Denis setting up Cigarini, who finished from just outside the box.
Despite Milan pressing for an equaliser, Atalanta held firm for a 1-0 win and the hosts now have three points from nine.