Two first-half goals against Palermo have put Napoli three points clear of Udinese, Inter Milan and Lazio in the race for the third Champions League place in Italy.
Gokhan Inler smacked the upright as the hosts made an encouraging start in the Stadio San Paolo.
They took the lead after a quarter of an hour when Edinson Cavani dispatched from 12 yards after Palermo's Milan Milanovic was adjudged to have handled in the area.
Marek Hamsik made it two 20 minutes later by finding the bottom left-hand corner after being played through by Goran Pandev.
Abel Hernandez came close to pulling a goal back before the interval but screwed his effort just wide of the post.
Napoli controlled the remainder of the affair, with Hernandez often the only threat for the visitors.
