Napoli can thank goalkeeper Pepe Reina for the three points.
A miraculous save from the Spanish shot-stopper in the dying minutes of second-half stoppage time preserved his team's 2-1 win over title rival Roma.
Roma kept Reina busy toward the end of the match, with substitute Mohamed Salah producing a couple of prime scoring chances before hitting the upright.
But it was teammate Diego Perotti's thumping effort that forced the best save out of the former Liverpool 'keeper.
Amid a helter-skelter season in Napoli's net, Reina came up with the goods at a crucial point of a flailing league campaign.
Goals from breakout Belgian Dries Mertens established a 2-0 lead, and although Kevin Strootman gave Roma life with an 89th-minute finish, it was Napoli which left the Stadio Olimpico with a vital win.
It cuts the Partenopei's gap behind league leader Juventus to nine points.
The Old Lady faces Udinese on Sunday afternoon.