Napoli's title hopes took another blow as Walter Mazzarri's team were frustrated by lowly Bologna, who held them to a 1-1 draw at the San Paolo Stadium on Monday.
Despite having recorded impressive wins over AC Milan, Inter Milan and Manchester City this season, Napoli have slipped up too often against supposed minnows.
And it happened again as they needed Edinson Cavani's penalty to cancel out Robert Acquafresca's early opener for the visitors.
The result left Napoli down in sixth and still 10 points off leaders Juventus while Bologna moved four points clear of the drop zone.
Bologna coach Stefano Pioli was proud of his team.
"We played a great game, it's not easy going to Napoli and keeping your head up against such a strong team with good organisation, a well-defined game-plan and quality players," he said.
Napoli were straight on the attack and Marek Hamsik should have given them an early lead when picked out by Hugo Campagnaro's cross, all alone, 10 yards out but his low finish was stopped by Jean-Francois Gillet.
Mazzarri was full of excuses and said he felt scoring then would have changed the game.
"My only regret is that chance Hamsik missed after a few minutes," he said.
"Bologna played well, they contained well and that countered, but then again everyone who comes here plays like that.
"We weren't very lucid tonight, there were too many players not at their best.
"We play with tempo and the pitch tonight didn't help us and then when you don't get a goal straight away and instead concede one you have to claw your way back and it was easier for Bologna."
The hosts were made to pay for that as Bologna scored out of nothing.
Camapagnaro failed to block Nico Pulzetti's through ball and Acquafresca was left all alone in front of goal to beat Morgan De Sanctis.
Hamsik came close again as he worked space on the edge of the box but his shot was deflected behind.
In the second half Bologna had a close shave as Goran Pandev took down a corner on the six-yard box but with his back to goal and under pressure he failed to get the contact needed to turn the ball home.
Napoli started getting desperate and Salvatore Aronica tried his luck from fully 30 yards, but although he hit it well, Gillet held on.
Drama broke out 20 minutes from time as Diego Perez was adjudged, perhaps harshly, to have handled the ball.
The referee originally gave a free-kick on the edge of the box but then changed it to a penalty on the linesman's advice.
Bologna defender Andrea Raggi gave Aronica a huge shove in the mayhem and protests that ensued but the referee didn't see it and it was left to Cavani to thrash home the spot-kick.
Pioli was fuming about that decision.
"The rule is clear, a handball has to be intentional to give a penalty but it was ball to hand, the rule wasn't properly applied," he moaned.
Captain Marco Di Vaio had two great late chances to snatch a victory on the counter-attack for the visitors but he was tackled by Juan Zuniga the first time and De Sanctis denied him on the second.