Milan - Mario Mandzukic scored in each half as Juventus came from behind to beat ten-man Napoli 3-1 and open up a six-point lead on Carlo Ancelotti's side at the top of the Serie A table.
Portuguese superstar Cristiano Ronaldo played a role in all three goals as Massimiliano Allegri's side ensured a maximum 21 points after seven games.
Napoli are on 15 points, after falling to their second defeat of the season.
"Ronaldo is enjoying his football, he has integrated very well," said Allegri.
"He's an extraordinary player, the passing is exceptional, and tonight was the best Ronaldo of the season, along with the high-level half-hour in Valencia."
In Turin, Ancelotti's first trip to his former club got off to a promising start when Jose Callejon volleyed for Dries Mertens to open the scoring after ten minutes.
But Ronaldo set up Mandzukic to head in the equaliser after 26 minutes.
The momentum then swung to Juventus with a Ronaldo effort ricocheting off the post and into the path of the onrushing Croat who tapped in four minutes after the break.
Napoli were struggling after Portuguese left-back Mario Rui was sent off on 58 minutes for a second bookable offence.
Ronaldo headed towards goal after a corner with centre-back Leonardo Bonucci sliding in the third on 76 minutes.
"I think the referee made a superficial decision. Mario Rui got the second yellow card after a good long wait to consider it," said Ancelotti.
"I was angry at my team because we started strong and took the lead, but then started getting sluggish and allowed Juventus to regain their confidence."
Both teams are in Champions League action next week with Juventus hosting Swiss club Young Boys without Ronaldo, who has a one-match ban after he was controversially sent off in the win over Valencia.
Napoli play at home against last year's runners-up Liverpool.
Earlier Lorenzo Pellegrini came off the bench and lifted Roma to a 3-1 win over bitter city rivals Lazio to revive his side's stumbling start to the season.
Eusebio Di Francesco's team had plunged into crisis after a 2-0 defeat to Bologna, but have now claimed consecutive wins for the first time this season after their 4-0 victory over Frosinone in midweek.
The win ended Lazio's four-match winning streak in Serie A and lifts Di Francesco's side into fifth just behind their city rivals with 11 points from seven games.
"We reacted as men today, which was what I had asked for," said Di Francesco.
"This performance means the team hasn't lost its identity or idea of football. I saw the difference in their faces and their eyes today, and it showed on the pitch."
Pellegrini came on after 35 minutes in place of Argentine Javier Pastore who hobbled off with a suspected calf injury.
And the 22-year-old transformed the must-win match in the Italian capital, opening the scoring just before half-time with a back-heel flick.
Lazio ace Ciro Immobile missed a chance for the equaliser moments later, but made no mistake after 67 minutes with an angled drive following a howler by Roma's Argentine defender Federico Fazio.
But minutes later Aleksandar Kolarov fired Roma ahead again after Pellegrini won a free kick which the Serb sent through the Lazio wall, to achieve the rare exploit of scoring for both Roma and former team Lazio, in 2009.
Fazio made up for his earlier error with Roma's third goal, heading a Pellegrini free kick into the far top corner four minutes from time.
"It hurts to lose a derby," said midfielder Marco Parolo, "but we have to look ahead, this team has shown they are able to get up and start again. We are still ahead of them."
Di Francesco's side take on Czech club Plzen in the Champions League on Tuesday.
Inter Milan warmed up for their Champions League trip to PSV Eindhoven with goals in either half from Lautaro Martinez and Matteo Politano giving them a 2-0 win over Cagliari at the San Siro.
Luciano Spalletti's Inter are fourth on 13 points ahead of Lazio (12) and Roma (11).