Substitutes Martin Caceres and Paul Pogba both struck in the last ten minutes to earn I Bianconeri all three points at the Juventus Stadium.
The hosts, who had chalked up six league wins and a draw under the guidance of Massimo Carrera, had to work hard for their win, though. Napoli started well and it was Edinson Cavani who came closest to breaking the deadlock in the first half.
Despite only arriving back from international duty on Friday, the Uruguayan showed no signs of jetlag as he curled a free-kick from wide left onto the crossbar with Juve goalkeeper Marco Storari, deputising for the injured Gianluigi Buffon, beaten.
Juve's first serious attempt on goal came in added time when Claudio Marchisio's 20-yard effort was tipped over the crossbar by Morgan de Sanctis.
Alessandro Matri only just failed to latch onto a delightful long ball from Andrea Pirlo, with De Sanctis racing off his line to clear the danger in the 66th minute.
Caceres replaced the injured Kwadwo Asamoah and Pogba also came on. With almost his first touch, Caceres put Juve in front with a committed header in the 80th minute, meeting Pirlo's corner six yards out.
Two minutes later, it was game over for Napoli as Paolo Cannavaro's clearance looped up and Pogba struck it first time with a fine left-foot volley from 25 yards which found the bottom right-hand corner of De Sanctis' goal.