Match ends, Milan 0, Atalanta 3.
AC Milan were outplayed by Atalanta at the San Siro as their Serie A lead over Inter Milan was cut to two points.
Cristian Romero headed home Robin Gosens' corner after 26 minutes before Josip Ilicic was brought down by Milan's Franck Kessie in the area midway through the second half.
Ilicic converted the penalty before Duvan Zapata added a third late on.
Inter, who could have gone level at the top with a win, were held to a goalless draw at Udinese.
Atalanta, who become just the second side to beat AC Milan in Serie A this season, rise to fourth in the table.
- 20Kalulu KyatengwaSubstituted forMusacchioat 57'minutes
- 19HernándezBooked at 37mins
- 79KessiéBooked at 51mins
- 7Castillejo AzuagaSubstituted forMandzukicat 70'minutes
- 18MeitéSubstituted forDíazat 45'minutes
- 17da Conceição LeãoSubstituted forRebicat 70'minutes
- 19DjimsitiSubstituted forCaldaraat 90+1'minutes
- 33HateboerSubstituted forMaehleat 67'minutes
- 15de Roon
- 8GosensBooked at 84minsSubstituted forPalominoat 90+1'minutes
- 32PessinaSubstituted forMalinovskiyat 90'minutes
- 72IlicicSubstituted forMurielat 82'minutes
- 59Al Miranchuk
- Maurizio Mariani
- Shots on Target
Second Half ends, Milan 0, Atalanta 3.
Attempt saved. Mario Mandzukic (Milan) left footed shot from the centre of the box is saved in the top centre of the goal. Assisted by Zlatan Ibrahimovic.
Attempt missed. Zlatan Ibrahimovic (Milan) header from the centre of the box misses to the right. Assisted by Theo Hernández with a cross.
Corner, Milan. Conceded by Mattia Caldara.
Attempt blocked. Brahim Díaz (Milan) right footed shot from outside the box is blocked.
Attempt blocked. Franck Kessié (Milan) header from the centre of the box is blocked.
Corner, Milan. Conceded by Marten de Roon.
Attempt missed. Marten de Roon (Atalanta) right footed shot from outside the box is high and wide to the right.
Substitution, Atalanta. Mattia Caldara replaces Berat Djimsiti.
Substitution, Atalanta. José Luis Palomino replaces Robin Gosens.
Substitution, Atalanta. Ruslan Malinovskiy replaces Matteo Pessina.
Foul by Mateo Musacchio (Milan).
Luis Muriel (Atalanta) wins a free kick in the defensive half.
Attempt blocked. Zlatan Ibrahimovic (Milan) right footed shot from the centre of the box is blocked. Assisted by Theo Hernández with a cross.
Hand ball by Duván Zapata (Atalanta).
Robin Gosens (Atalanta) is shown the yellow card for a bad foul.
Davide Calabria (Milan) wins a free kick on the right wing.
Foul by Robin Gosens (Atalanta).
Substitution, Atalanta. Luis Muriel replaces Josip Ilicic.