The Bianconeri opened the scoring just 10 minutes in through Giorgio Chiellini but Gokhan Inler earned the hosts a share of the spoils with a deflected effort from distance
Antonio Conte's men looked poised to take a giant step towards retaining their title after taking an early lead through Giorgio Chiellini, but Gokhan Inler's deflected drive drew the home side level just before the break.
Napoli looked the slightly more likely victor during the second period but Juventus held on quite comfortably to keep its nearest challenger at arm's length.
The only doubt Conte had had before the game was over whether to start Chiellini, who took a knock to his ankle against Siena last weekend. The Bianconeri boss decided to take a gamble on the Italy international - and it paid off spectacularly just 10 minutes in, Chiellini rising above Miguel Britos to powerfully head a terrific cross from Andrea Pirlo past Morgan De Sanctis.
The goal was harsh on Napoli, which had actually begun the brighter of the two, with Marek Hamsik particularly prominent early on. However, as soon as Juventus scored, everything changed, and Mirko Vucinic had already squandered one decent headed opening when he butchered a gilt-edged opportunity to double the visitors’ advantage.
Leonardo Bonucci - of all people - then dissected the Partenopei defense with a perfectly-weighted pass from deep that Arturo Vidal, in a sensational demonstration of awareness, controlled, before immediately flicking inside to Vucinic. The Montenegrin, as he so often does, took an age to decide how best to finish, thus allowing De Sanctis to narrow the angle sufficiently to block the Bianconeri forward’s belated strike on goal away for a corner.
Such profligacy rarely goes unpunished at the top level and so it was that Napoli managed to haul itself level during a dramatic conclusion to a compelling opening 45 minutes. There appeared to be little danger to the Juventus goal when Inler picked up possession some 30 yards out, but the Swiss international’s well-struck drive from distance took a small but significant deflection off the head of Bonucci, sending it flying over the despairing dive of Gianluigi Buffon.
That was the first stroke of luck Napoli benefited from on the night; the second arrived in the dying seconds of the first half when star striker Edinson Cavani inexplicably avoided a straight red card for a blatant forearm into Chiellini’s face. In his defense, Daniele Orsato, did not see what was an off-the-ball incident, but quite why he decided to brandish only a yellow after being informed of what had happened by one of his assistants was utterly mystifying, though subsequent television replays suggested that there had perhaps been some sort of provocation.
Napoli did its utmost to make the most of its undoubted good fortune, with Hamsik drawing a fine stop out of Gianluigi Buffon shortly after halftime. However, Vucinic responded in kind, bringing the best out of De Sanctis, as Juve redoubled its efforts to all but end the title race.
Napoli, though, was left cursing its own inability to draw to within three points of its opponent after wasting a terrific chance to snatch a vital win. Just moments after Cavani had headed straight at Buffon, Hamsik again found some space in between the Juve midfield and defense. The Slovak unleashed a powerful drive that Buffon found too hot to handle, but Lorenzo Insigne, who had replaced the grossly ineffective Goran Pandev, snatched at the rebound and dragged the ball wide. And with it, went Napoli's best chance to breathe new life into the Scudetto race.