Hat-tricks from Marek Hamsik and Dries Mertens helped a sensational Napoli trounce Bologna 7-1 away from home on Saturday to move to within three points of Serie A leaders Juventus.

Napoli enjoyed a lightning start at Stadio Renato Dall'Ara, scoring twice in the first six minutes thanks to cool finishes from Hamsik and Lorenzo Insigne.

Bologna wasted the opportunity to pull one back as Pepe Reina saved a Mattia Destro penalty, but they did receive a boost shortly after when Jose Callejon – guilty of the handball offence that resulted in the spot-kick – was sent off for kicking out at Adam Nagy.

That numerical advantage did not last long, though, as Adam Masina was harshly shown a straight red for tripping Mertens when through on goal despite Vasilis Torosidis also covering, and the Belgian swept in the subsequent free-kick.

Torosidis gave Bologna's chances a slight boost in the 36th minute with a tap-in, but Mertens scored again just before the break, rounding Antonio Mirante in composed fashion before slotting into an empty net.

The second period was not quite so frantic, but Napoli continued to look ruthless in attack – Hamsik completing his hat-trick with two exquisite finishes into the top-right corner to make him Napoli's second-highest goalscorer with 109, six short of Diego Maradona.

Mertens then added their seventh late on, smashing home in emphatic fashion to secure Napoli's record away win in Serie A.