Napoli wasted a chance to provisionally reclaim the top spot in the Serie A standings for the first time since February when they were held to a 0-0 draw at second-from-bottom Venezia on Sunday.
Napoli remained in second place with 61 points from 29 matches - level with leaders Inter Milan and three points ahead of third-placed Atalanta, who face each other later on Sunday.
Both sides had opportunities to score in an even first half at the Pier Luigi Penzo Stadium, with Napoli's Giacomo Raspadori hitting the post while Venezia forward Daniel Fila was denied by a brilliant last-ditch block from Amir Rrahmani.
Antonio Conte's team continued to turn the screw after the interval but they were unable to break down a resolute Venezia, who have now conceded just once in four league games - a run in which they also held top-five sides Lazio and Atalanta to goalless draws.
