Cavani hat-trick helps reduce gap
The Uruguayan scored a hat-trick with Marek Hamsik also on target for the hosts. The thumping win saw Napoli close the gap on Milan to four points. Defeat, though, made it three league games without a win or even so much as a goal for Samp, whose European hopes suffered a blow.
It was Samp who started the brighter, though, and on-loan striker Federico Macheda had a shot saved by Morgan De Sanctis, who was also equal to Stefano Guberti's effort from distance.
But Napoli went ahead in the 16th minute as Ezequiel Lavezzi set up Cavani to find the corner from close range.
The home side were now up and running and Hassan Yebda's shot grazed the left post before Cavani wasted a golden chance to capitalise on a mix-up between Samp goalkeeper Gianluca Curci and defender Pietro Accardi.
The striker did punish an Accardi indiscretion on the stroke of half-time, though, converting a penalty into the bottom corner after he had been brought down in the area.
Hamsik put the result beyond doubt three minutes after the restart as he took advantage of another Lavezzi assist to fire home. And it became four in the 57th minute as Cavani completed his treble with a close-range finish.
The Uruguayan had another chance to add to Samp's misery only to head wide, while Lavezzi came close to getting the goal his performance deserved but shot over as Napoli dominated to the end.