Juventus earns statement win
After leaders Roma were held to a 1-1 draw by Sassuolo earlier on Sunday, Juve ominously moved to within a point of the capital club following goals from Fernando Llorente, Andrea Pirlo and Paul Pogba.
Only the late dismissal of Angelo Ogbonna soured an otherwise memorable day for Antonio Conte's side, who have now won eight of their past nine league games.
Napoli goalkeeper Pepe Reina was busy throughout and he had already kept out a Pogba strike before Llorente opened the scoring with just two minutes played.
Reina was forced into more action shortly after to deny Mauricio Isla and Leonardo Bonucci.
Napoli had been on the back foot for the first 20 minutes before Lorenzo Insigne drew a low save from Gianluigi Buffon.
Gonzalo Higuain then skimmed the crossbar after bringing the ball down on his chest.
Chances were shared at both ends but Reina was forced to make the better saves, again showing his agility to prevent Llorente grabbing a second just before half-time.
When the second half began Napoli made a couple of early raids, Insigne shooting narrowly over before seeing Buffon get down to a free-kick that was on target, before Reina was at the heart of matters again.
The on-loan goalkeeper blocked from Arturo Vidal with Carlos Tevez unable to steer the rebound on target.
Juve finally did go 2-0 up on 74 minutes through their veteran Italy midfielder Pirlo.
The 34-year-old left Reina with no chance as he arrowed a free-kick into the top corner.
Pogba then put the seal on the contest with 10 minutes left, firing in from the edge of the area, although Ogbonna saw red three minutes later.
The defender brought down Dries Mertens and as the last man had to go, although the game was already decided by then.