Cristiano Ronaldo erased the frustration of his Champions League red card midweek by scoring the opener and setting up Federico Bernardeschi for a second as Juventus kept their perfect record in Serie A after five games with a 2-0 win a promoted Frosinone on Sunday.
The Portugese star had threatened several times at the Stadio Benito Stirpe but finally found a way through nine minutes from time, and then helped Italian Bernardeschi to score Juve's second four minutes into injury time.
The five-time Ballon d'Or winner had scored his first goals last week with a double in a 2-1 win over Sassuolo, before the 33-year-old was sent off on Wednesday in a 2-0 Champions League win over Valencia.
Juventus -- the only unbeaten team in Serie A -- have 15 points from five games, three points ahead of Napoli who beat Torino 3-1 earlier on Sunday.
Seven-time reigning champions Juventus and Napoli, last season's runners-up, will go head-to-head next Saturday in Turin.
Frosinone had frustrated the champions for long periods but caved in late and have now conceded 12 goals to remain second bottom of the table with just one point.
Earlier Lorenzo Insigne bagged a brace to inspire Napoli to a 3-1 win in Torino as Roma plunged further into crisis with a 2-0 loss at Bologna.
In Turin, Ancelotti switched things around following Napoli's uninspiring goalless draw at Red Star Belgrade in the Champions League midweek.
Insigne played a more central role along with Dries Mertens as defender Sebastiano Luperto got his first start for the Serie A runners-up.
"I'm satisfied, we dominated in Belgrade but we couldn't finish things off like we did today," said Ancelotti.
"Insigne was decisive, but everyone put in a strong performance."
The Italy winger got the first after just four minutes when poor Torino defending saw Emiliano Moretti clear to Nicolas N'Koulou with the rebound favouring Insigne, who finished off under the crossbar.
Simone Verdi added the second with a half-volley on 20 minutes, with Torino pulling one back after the break when Andrea Belotti slotted in a penalty.
But Insigne restored Napoli's two-goal lead after 59 minutes.
Torino are in 15th position with five points from as many games.
- Roma in crisis -
However, Roma coach Eusebio Di Francesco is under increasing pressure after a fourth league game without a win sees last year's third-placed team slump to 14th with five points from as many games.
"The facts condemn us, they condemn me. Clearly something has to change. I feel I'm one of those to blame," said Di Francesco.
"There's no inner fire."
Federico Mattiello curled in Bologna's first goal of the season after 36 minutes with Paraguayan Federico Santander adding the second after 59 minutes.
Bologna remain 18th after their first win of the season.
Roma -- last year's Champions League semi-finalists -- also fell 3-0 at Real Madrid midweek, and have not won a league game since their first game against Torino.
Next weekend Roma face bitter city rivals Lazio, who saw off Genoa 4-1 on Sunday with Ciro Immobile scoring a double, to move up to fifth place.
Inter Milan snatched a late 1-0 win against Sampdoria in Genoa on Saturday to move up to ninth, but city rivals AC Milan were held 2-2 by Atalanta on Sunday despite leading twice at the San Siro.
Gonzalo Higuain volleyed in for Milan after just two minutes, but Papu Gomez snatched the equaliser on 54 minutes. Giacomo Bonaventura had a goal disallowed in the first half but made no mistake after 61 minutes, only for Emiliano Rigoni to snatch a point for the visitors in injury time.