Unbeaten Juventus are eight points clear at the top of Serie A after a deserved victory over Roma.
Mario Mandzukic scored the only goal when he headed home from Mattia de Sciglio’s cross.
Juve substitute Douglas Costa had a goal ruled out late on after a long video assistant referee delay following a foul in the build-up.
Roma would have lost by more if not for goalkeeper Robin Olsen, who denied Cristiano Ronaldo three times.
The Swede made two excellent stops from Ronaldo, who had 10 of Juve’s 20 shots, and another two to deny Alex Sandro in the first half.
Juve captain Giorgio Chiellini had a header disallowed for a foul on the goalkeeper, although it appeared to be a harsh decision.
Ronaldo also missed the target with a bicycle kick.
Juventus – with 16 wins and a draw – have the best record of any club after 17 games of a Serie A season. They are eight points above second-placed Napoli, who beat SPAL 1-0.
The champions are 16 points clear of third-placed Inter Milan, who drew 1-1 at Chievo.
Roma drops into 10th position, with manager Eusebio di Francesco under pressure.