Napoli moved seven points clear at the top of Serie A with a clinical 2-0 win at AC Milan.
Former Inter Milan forward Romelu Lukaku made an instant impact on his return to the San Siro, opening the scoring after five minutes as he outmuscled Strahinja Pavlovic inside the penalty area before firing into the bottom corner.
Despite a response from Milan, who tested Napoli goalkeeper Alex Meret on a handful of occasions, Khvicha Kvaratskhelia doubled the lead for the visitors minutes before half-time.
The Georgia international embarked on one of his trademark mazy runs down the left wing, chopping past several defenders before unleashing a curling drive beyond the hands of Mike Maignan.
Immediately after the restart the hosts looked to have halved the deficit through Alvaro Morata but his header was ruled out for a marginal offside.
Victory takes Antonio Conte’s side to 25 points, seven clear of Inter Milan in second.
A third defeat of the season leaves AC Milan in eighth place, 11 points off the pace.