Romelu Lukaku scored a double as Inter comfortably beat Napoli 3-1 for their first Serie A win at the San Paolo in just over 22 years.
Inter were on Monday briefly replaced at the top of the league by Juventus, who downed Cagliari 4-0, but regained their spot at the summit with an impressive triumph.
Lukaku struck twice in the first half, the second coming thanks to a blunder from Napoli goalkeeper Alex Meret, before Arkadiusz Milik halved the deficit in the 39th minute.
Lautaro Martinez made sure of the result in the second half, with the victory Antonio Conte's 100th as a coach in Serie A.
Giovanni Di Lorenzo was punished for an unfortunate slip in the 14th minute, as Lukaku latched onto the loose ball and raced forward to fire in off the left post.
Meret did well to deny Matias Vecino and Martinez but he undid his good work in the 33rd minute when he diverted Lukaku's powerful drive from 18 yards between his own legs and in.
Napoli stayed positive and, after Samir Handanovic just about kept out Lorenzo Insigne, Jose Callejon squared Piotr Zielinski's diagonal delivery into the six-yard box for Milik to tap home before the break.
The tempo dropped off in the second half but Inter again made Napoli pay for an error. Kostas Manolas was unable to clear Vecino's right-wing delivery and instead teed up Martinez to stab home with 62 minutes played.
Tempers flared when Fabian Ruiz forcefully kicked the ball into the Inter dugout, with Sebastiano Esposito and Antonio Conte going into the book for their reactions.
Insigne clipped the crossbar with a 20-yard free-kick as Napoli proved unable to spark a comeback with 15 minutes remaining.
Martinez almost doubled his tally in stoppage time but, after rounding Meret, was dispossessed by Di Lorenzo, who looked fortunate not to concede a penalty for his challenge.
Conte brings up his ton
Conte's first win as a Serie A coach came in October 2009 while in charge of Atalanta and he reached 100 victories in 145 matches. That is the quickest of any boss to have made their debut in the division from 1994-95 onwards. He will hope to keep up the impressive pace and lead Inter to their first Scudetto since 2010.
Lukaku looking sharp
Lukaku has been prolific away from home this season and now has 10 goals in his nine appearances on the road. He was a threat from the off and thoroughly deserved his brace.
A demerit for Napoli's keeper
After making decent saves from Vecino and Martinez, Meret committed a howler when he let Lukaku's stinging shot squirm through him to hand Inter a 2-0 lead.
