Napoli's title hopes took a further blow as Carlo Ancelotti's side were held to a goalless draw for the third time in four league matches to drop further points against Torino and trail champions Juventus by 13 points.
Napoli had drawn at home against AC Milan two weeks ago and at Fiorentina last time out and will face a top-of-the-table clash against Juventus on March 3 with their Serie A bid already all but over.
Champions Juventus are firmly on track for an eighth consecutive title after Cristiano Ronaldo scored in a 3-0 win over lowly Frosinone on Friday.
"We played with focus, motivation, determination, but it's unacceptable to have 18 scoring opportunities over two games and not score any of them," Ancelotti told Sky Sport Italia on Sunday.
Napoli proved wasteful at the San Paolo Stadium with Arkadiusz Milik missing a string of chances to break the deadlock as Lorenzo Insigne hit the post in the 74th minute.
On-loan Chelsea defender Ola Aina threatened for Torino in the dying minutes but was chased down by Brazilian Allan as Walter Mazzarri's side stayed ninth - three points off the Europa League places.
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Earlier Sunday, Radja Nainggolan scored the winner for Inter Milan to consolidate third position with a 2-1 win over Sampdoria at the San Siro, while Lazio's Champions League hopes took a knock with defeat by Genoa.
Nainggolan rifled in low on 78 minutes after Danilo D'Ambrosio had opened the scoring five minutes earlier, with Manolo Gabbiadini equalising for Sampdoria in between.
It was the Belgian's third goal this season and gave Inter a third straight win after a recent slump as Luciano Spalletti's side sit seven points adrift of Napoli in third.
Argentine forward Mauro Icardi watched from the stands, along with his wife Wanda Nara, who is also his agent, after being stripped of the captaincy amid protracted contract negotiations.
"I very much appreciated that he was in the stadium," said Spalletti of Icardi who missed the last two games with a reported knee injury.
"I would have liked even more if he had come into the dressing room afterwards to celebrate with us, as it was a very important victory."
- Lazio sink in Genoa -
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