Lorenzo Insigne struck twice and set up another as Napoli romped to a 4-0 win over AC Milan at the San Siro.
Allan put Napoli on their way to a first away league win of the season in the 13th minute before Insigne, who created that chance, doubled the visitors' advantage three minutes after the re-start.
The Italy forward added his second of the evening in the 67th minute before an own goal from Milan defender Rodrigo Ely with 13 minutes left completed the scoring as Napoli ended the Rossoneri's 100 percent home record this season in style.
The victory lifted Napoli to sixth in the standings, six points adrift of league leaders Fiorentina heading into the international break.
Milan, meanwhile, dropped to 11th place after suffering their fourth defeat of the season and second on the trot.
Napoli went into the contest looking to complete a perfect week after following their 2-1 triumph over Juventus with Thursday's 2-0 win at Legia Warsaw in the Europa League.
The Rossoneri, without injured striker Mario Balotelli, struggled to find a way through Napoli's defence and had just two shots on goal in the match.
Milan went behind after a mistake from Cristian Zapata, who gave the ball away in his own half for Insigne to send Allan through on goal and the Brazilian midfielder beat Milan goalkeeper Diego Lopez in a one-on-one.
Napoli almost made it 2-0 before the interval when Marek Hamsik's cross found Gonzalo Huguain in the box and his back-heel flick was deflected by Zapata for a corner.
The visitors continued to press forward in the second half and were rewarded in the 48th minute.
Insigne played a one-two with Higuain before hitting a right-footed shot across Lopez and inside the far post.
Milan almost reduced the arrears before the hour.
Ely got away from his marker and headed Giacomo Bonaventura's cross on target but his effort was saved by Napoli goalkeeper Jose Reina.
Napoli made it 3-0 shortly after when Insigne curled a free-kick beyond Lopez's reach to notch his second of the night.
Milan conceded another goal 10 minutes later with Lopez left helpless as Faouzi Ghoulam's cross into the Milan area was deflected into his own net by Ely.
The hosts had the last chance of the game a minute from time but Bonaventura saw his powerful free-kick kept out by Reina.
The loss was Milan's worst home defeat since losing 4-0 to Inter Milan in the 2009-10 campaign.
Milan, who had won their opening two home games, have failed for a seventh straight game to keep a clean sheet and have plenty of work to do during the international break.