An injury-time blunder from Salvatore Aronica gifted Torino an equaliser as Napoli failed to significantly close the gap on Serie A's top two, Juventus and Inter Milan.
The home side seemed set to register just their second win in six games in all competitions when the returning Edinson Cavani put them in front after six minutes.
But Aronica, who had only been on the field five minutes when he attempted a back pass which was intercepted by Gianluca Sansone.
Sansone then displayed commendable calm to round home keeper Morgan De Sanctis and slot into an empty net.
It was hard on Napoli who had the majority of chances in an open game.
They took the lead from their first serious attack as Cavani, back from injury, slotted home from close range.
Marek Hamsik almost made it 2-0 12 minutes later but shot narrowly over the bar at the end of a swift counter-attack led by Blerim Dzemaili.
Dzemaili himself threatened again shortly after the half-hour mark with a shot which flashed wide from 25 yards.
It took Torino 35 minutes to muster an attempt on goal with Rolando Bianchi forcing De Sanctis into action with a header which the keeper saved smartly down at his near post.
Uruguay international Cavani was involved in the final action of the first half with a flashing header from a Hamsik corner which drifted well wide of the target.
The teams traded long-range efforts after the break - Alessandro Gazzi shooting over for Torino with Andrea Dossena replying with a cross-shot for Napoli which was well wide.
Torino were working hard in search of an equaliser and both Alessio Cerci and Mario Santana had opportunities which they failed to take, Cerci volleying wide and Santana seeing a long-range effort easily saved by De Sanctis.
But in pushing forward they left gaps at the back from which Napoli should have capitalised and put the result beyond doubt after 85 minutes.
Hamsik was put in on goal and he skipped round Torino goalkeeper Jean-Francois Gillet but inexplicably shot wide with the net gaping.
It was to prove a costly miss as Aronica's gaffe allowed Sansone the chance to equalise and deny Napoli the opportunity to close to within two points of second-placed Inter.