Lorenzo Insigne scored twice as Napoli turned on the style to continue a fine run of form in a 4-0 rout at Milan on Sunday.

Italy international Insigne was a scorer in Napoli's 2-1 win against Serie A champions Juventus last weekend, and he was on target twice in the second half against a hapless Milan, who suffered their biggest home defeat in six years since losing 4-0 to a Jose Mourinho-led Inter.

Napoli were more than good value for the scoreline and victory at San Siro stretches their unbeaten run in all competitions to eight matches.

Maurizio Sarri's side were given a helping hand for the first goal as Cristian Zapata's woeful defensive clearance led to a swift counter-attack that was clinically finished by Allan.

But there was no luck about the second goal shortly after the break as Insigne combined brilliantly with the impressive Gonzalo Higuain before bending home.

Insigne was celebrating again in the 67th minute after netting  an excellent 30-yard free-kick, before Rodrigo Ely's own goal summed up Milan's misery.

Sinisa Mihajlovic has thus far failed to break Milan from their recent struggles and, though his side dominated possession in the opening stages, they only had a harmless long-range effort from Ricardo Montolivo and a scuffed shot from Juraj Kucka to show for their efforts.

And their failure to use the ball better was punished by Napoli in the 13th minute.

Marek Hamsik seized upon Zapata's poor clearance to feed Insigne and he in turn played a neat throughball to Allan, who coolly slotted past Diego Lopez when one-on-one.

Higuain then showed great skill to bring down a long pass and turn Zapata in one fluid movement, but his resulting shot was tame and gathered by Lopez.

The Argentina striker was proving a threat and he fired another warning with a flashed shot across goal from the right of the penalty area.

For all Milan's endeavour they produced little in terms of goal threat, and Napoli clinically doubled their lead three minutes after the break.

Insigne played a brilliant one-two with Higuain and curled his shot from the left of the penalty area into the far corner past a helpless Lopez.

Milan forced a rare effort on target when Ely's flicked header from Giacomo Bonaventura's cross was well held by Pepe Reina.

But Insigne put the game beyond all doubt with just over 20 minutes remaining with a sublime curling free-kick that Lopez got his hands to but was unable to stop nestling in the left-hand corner.

There was worse to come for Milan, though, as Ely slid in to clear Faouzi Ghoulam's cross and succeeded only in stabbing into his own goal, leaving Mihajlovic with plenty to ponder heading into the international break.