Match ends, Milan 0, Juventus 2.
Gonzalo Higuain missed a penalty and was sent off against his former side Juventus as AC Milan slumped to a home defeat by the Italian champions.
Mario Mandzukic's header put league leaders Juve ahead after eight minutes.
Higuain had the chance to level from the spot but saw his low effort tipped onto the post by Wojciech Szczesny.
Cristiano Ronaldo settled the points nine minutes from time, before Higuain lost control, picking up two quick yellow cards and raging at the referee.
First the Argentina striker was booked for a foul on Juve defender Medhi Benatia, with his second coming moments later for dissent as he shouted in the match official's face.
Higuain, 30, signed for Milan in August in a loan deal that will be made permanent next year, with Leonardo Bonucci moving the other way.
The man who took his place at Juve, £99.2m signing Ronaldo had just minutes before converted a rebound in the box for his eighth league goal in 12 matches since arriving from Real Madrid.
The Turin club, league champions in each of the past seven seasons, are six points clear of Napoli and unbeaten at the top of Serie A, while Milan are fifth, 13 points behind.
Earlier on Sunday, third-placed Inter Milan were beaten 4-1 at Atalanta while Roma climbed up to sixth with a 4-1 victory at home to Sampdoria.
- 99G Donnarumma
- 20AbateSubstituted forBoriniat 74'minutesBooked at 87mins
- 8Fernández Saez
- 14BakayokoBooked at 61mins
- 10CalhanogluSubstituted forLaxaltat 74'minutes
- 7Castillejo AzuagaSubstituted forCutroneat 62'minutes
- 9HiguaínBooked at 83mins
- 90A Donnarumma
- 4BenatiaBooked at 34mins
- 12Lobo Silva
- 5PjanicSubstituted forKhediraat 74'minutes
- 10DybalaSubstituted forDouglas Costaat 79'minutes
- 7Cristiano Ronaldo
- 2De Sciglio
- 11Douglas Costa
- Paolo Silvio Mazzoleni
- Shots on Target
Second Half ends, Milan 0, Juventus 2.
Foul by Rodrigo Bentancur (Juventus).
Patrick Cutrone (Milan) wins a free kick in the defensive half.
Attempt missed. João Cancelo (Juventus) left footed shot from outside the box is just a bit too high. Assisted by Douglas Costa.
João Cancelo (Juventus) wins a free kick in the defensive half.
Foul by Diego Laxalt (Milan).
Fabio Borini (Milan) is shown the yellow card for a bad foul.
Blaise Matuidi (Juventus) wins a free kick on the left wing.
Foul by Fabio Borini (Milan).
Foul by Alex Sandro (Juventus).
Fabio Borini (Milan) wins a free kick in the defensive half.
Gonzalo Higuaín (Milan) is shown the red card.
Gonzalo Higuaín (Milan) is shown the yellow card.
Medhi Benatia (Juventus) wins a free kick in the attacking half.
Foul by Gonzalo Higuaín (Milan).
Goal! Milan 0, Juventus 2. Cristiano Ronaldo (Juventus) right footed shot from the centre of the box to the high centre of the goal.
Attempt saved. João Cancelo (Juventus) right footed shot from the right side of the box is saved in the centre of the goal. Assisted by Sami Khedira.
Mario Mandzukic (Juventus) wins a free kick on the left wing.
Foul by Franck Kessié (Milan).