Napoli 2-1 AC Milan

Lorenzo Insigne (centre) has scored three goals in 21 games for Italy

Napoli moved four points clear at the top of Serie A with an assured home victory over struggling AC Milan.

Lorenzo Insigne - the forward Italy whom did not bring on as they failed to qualify for the World Cup on Monday - opened the scoring with his seventh goal of the season in all competitions.

The goal was initially ruled out for offside but, after consulting with his video assistant, the referee gave it.

Piotr Zielinski doubled Napoli's lead after the break, before Alessio Romagnoli's brilliant consolation in injury time.

The Milan defender hammered a 92nd-minute volley into the bottom corner, giving his outplayed side brief hope of an unlikely comeback.

Second-placed Juventus travel to Sampdoria, who are sixth, on Sunday at 14:00 GMT.

Milan stay seventh as they continue to disappoint following a summer transfer window in which they spent about £210m on players.