Rodrigo Bentancur and Giorgio Chiellini scored and Cristiano Ronaldo added a late penalty to condemn Fiorentina to its first defeat of the season.
Fiorentina dominated for large periods and tested Wojciech Szczesny several times before Juventus doubled its lead and essentially sealed the result.
Second-placed Napoli visits Atalanta on Monday, the day after third-placed Inter Milan travels to Roma.
Juventus hosts Inter on Friday.
"We have started a tough month, with difficult away matches, in the best way possible," Chiellini said. "December will be important. At the end of the month we can do a first evaluation. But there's still a long way to go until May."
JUVE BLOOM AT FIORENTINA There was a touching moment before the match when Chiellini led Juventus to lay a bouquet of flowers in front of the home fans in tribute to former Fiorentina captain Davide Astori, who died in March of suspected cardiac arrest at the age of 31.
Juventus appealed for a penalty in the 25th minute when Mattia De Sciglio's cross hit Cristiano Biraghi's trailing arm but, after reviewing the incident on the pitchside monitor, the referee ruled it unintentional.
The visitors took the lead shortly after and Ronaldo was again involved. The Portugal star took away two defenders with a clever run, allowing Bentancur to play a swift one-two with Paulo Dybala and finish into the bottom right corner.
Fiorentina fought hard for the equalizer and went close but Chiellini scored his first goal for two years in the 69th minute.
Juve's second goal came from a rare source, but its third came from a natural goalscorer.
Fiorentina defender Vitor Hugo blocked Mario Mandzukic's cross with his hand and Ronaldo stepped up to powerfully dispatch the resulting penalty. It was his 10th goal in his past 11 Serie A matches.
Kathryn Mayorga filed a civil lawsuit in September in Nevada claiming Ronaldo raped her in his Las Vegas hotel room in 2009. Police reopened an investigation into the allegation at her request. Ronaldo has denied any wrongdoing.
SPAL 10 FORCE DRAW Spal managed to snatch a point against fellow struggler Empoli despite being reduced to 10 men.
Spal was trailing 2-1 when Thiago Cionek was sent off in the 49th minute for a last-man foul on Antonino La Gumina.
However, Jasmin Kurtic headed in the equalizer in the 67th, his second goal of the match.
Spal moved three points above the relegation zone and remained a point ahead of Empoli.
PRESSURE ON INZAGHI Andrea Poli and Gaston Ramirez scored against their former clubs but it was the latter who ended the night happier as Sampdoria crushed Bologna 4-1.
The result piles even more pressure on Bologna coach Filippo Inzaghi. Bologna is without a win since September and is a point from safety.