Cristiano Ronaldo continued his superb scoring form as Juventus won 2-1 away to AS Roma on Sunday and moved two points clear at the top of Serie A.
Merih Demiral put the Italian champions ahead early on before Ronaldo fired home a penalty to double their advantage with just 10 minutes played.
It was Ronaldo's 14th league goal of the season and his ninth in the last six Serie A appearances.
Things got worse for Roma towards the end of the first half when winger Nicolo Zaniolo was taken off in tears on a stretcher, and the club confirmed at full-time that the 20-year-old has ruptured the anterior cruciate ligament in his right knee.
The result leaves Juventus on 48 points at the top of the table at the midway stage of the season, two ahead of Inter Milan, while Roma are fifth on 35 points.
"We played well for a good 60 minutes, and suffering at the Stadio Olimpico against Roma is almost inevitable," Juventus coach Maurizio Sarri told Sky Sport Italia.
"What I did not like is that we tried to sit on our lead rather than increase it, as three times we had three-against-one counter-attacks and didn't finish them off."
Juve were in front after three minutes when Demiral volleyed home a Paulo Dybala delivery.
Dybala then robbed Roma midfielder Jordan Veretout of possession before being hauled down inside the box to earn his side a penalty, which Ronaldo dispatched to give the visitors a dream start.
Juve lost Demiral to injury after 17 minutes, but there were graver concerns for Zaniolo as he was carted off the pitch.
Roma confirmed after full-time that the Italy international will undergo surgery on Monday after rupturing the ACL in his right knee, along with damaging the meniscus.
"This is a bad moment and now Nicolo has to focus only on recovering as quickly as possible," Roma coach Paulo Fonseca told Sky Sport Italia.
"We are sad, but tomorrow is another day."
The Brazilian was adjudged to have handled following a Video Assistant Referee (VAR) review, and Perotti sent Wojciech Szczesny the wrong way from 12 yards.
There were late chances at both ends as Ronaldo headed wide from a good position, before Roma midfielder Lorenzo Pellegrini lashed over inside the box.
Earlier, Hellas Verona came from behind to beat Genoa 2-1 and rise to eighth in the standings on 25 points, leaving the relegation battling visitors stranded in 18th place with 14 points.