Match ends, Atalanta 5, Milan 0.
AC Milan suffered their heaviest defeat for more than 21 years as they were thrashed 5-0 by Atalanta in Serie A.
Stefano Pioli's side are 10th in the table and could go into Christmas in the bottom half if Sassuolo or Bologna win later on Sunday.
Alejandro Gomez scored a stunning opener, nutmegging Andrea Conti before firing home, and Atalanta's final three goals came in the last half hour.
Mario Pasalic scored and Josip Ilicic netted twice before Luis Muriel struck.
Atalanta, who are in the Champions League knockout stages, rise to fifth in the table.
Milan had not lost by five goals in any competition since being beaten 5-0 by Roma in May 1998.
Pioli, the club's third manager of 2019, said: "This cannot be the real Milan.
"[We] approached the match in the wrong way and you just can't afford to do that against this team.
"Today's performance was seriously insufficient. I expected a reaction from us in the second half but it didn't come. In fact, we were even worse."
- 21CastagneBooked at 46mins
- 15de RoonBooked at 56mins
- 8GosensSubstituted forHateboerat 89'minutes
- 10GómezSubstituted forFreulerat 88'minutes
- 72IlicicSubstituted forMurielat 80'minutes
- 41Ibañez da Silva
- 99G Donnarumma
- 22MusacchioBooked at 37mins
- 13RomagnoliBooked at 71mins
- 68RodríguezSubstituted forCalabriaat 45'minutes
- 79KessiéBooked at 77mins
- 5BonaventuraSubstituted forPiatekat 61'minutes
- 8Fernández SaezBooked at 44minsSubstituted forCastillejo Azuagaat 84'minutes
- 17da Conceição Leão
- 7Castillejo Azuaga
- 90A Donnarumma
- Federico La Penna
- Shots on Target
Second Half ends, Atalanta 5, Milan 0.
Corner, Milan. Conceded by Timothy Castagne.
Attempt blocked. Franck Kessié (Milan) left footed shot from the centre of the box is blocked.
Corner, Milan. Conceded by Hans Hateboer.
Substitution, Atalanta. Hans Hateboer replaces Robin Gosens.
Substitution, Atalanta. Remo Freuler replaces Alejandro Gómez.
Foul by José Luis Palomino (Atalanta).
Krzysztof Piatek (Milan) wins a free kick in the attacking half.
Attempt saved. Robin Gosens (Atalanta) right footed shot from the left side of the box is saved in the bottom right corner. Assisted by Berat Djimsiti.
Corner, Atalanta. Conceded by Davide Calabria.
Marten de Roon (Atalanta) wins a free kick in the defensive half.
Foul by Rafael Leão (Milan).
Substitution, Milan. Samu Castillejo replaces Suso.
Goal! Atalanta 5, Milan 0. Luis Muriel (Atalanta) right footed shot from the centre of the box to the centre of the goal.
Attempt blocked. Timothy Castagne (Atalanta) left footed shot from very close range is blocked.
Attempt saved. Timothy Castagne (Atalanta) right footed shot from the centre of the box is saved in the centre of the goal. Assisted by Robin Gosens.
Substitution, Atalanta. Luis Muriel replaces Josip Ilicic.
Franck Kessié (Milan) is shown the yellow card for a bad foul.
Ruslan Malinovskiy (Atalanta) wins a free kick on the left wing.