Cavani double sinks City
Naples - Napoli stunned Manchester City 2-1 at the San Paolo stadium here on Tuesday to leave the English Premier League leaders' Champions League hopes in the balance.
Napoli now lead City by a point heading into the final Group A games in two weeks time in which the Italians will travel to pointless Villarreal while the English team will host already qualified group winners Bayern Munich.
Edinson Cavani scored a brace for the hosts either side of a Mario Balotelli tap-in.
"We'll enjoy this wonderful moment, we always knew, right from the first day, that we could do it," said the match-winner.
"We always prepare to give the maximum and today we gave our all."
City coach Roberto Mancini was disappointed with his team's defending.
"I don't think we deserved to lose the game, but we did concede two stupid goals," he said.
"We knew Cavani would be on the near post for the first goal, and we didn't mark him for the second.
"After our equaliser we had two chances to go 2-1 up so it was strange that we conceded.
"This is the Champions League, never say never."
City bossed the early stages as Pablo Zabaleta crossed from the right but Edin Dzeko was over ambitious and the chance went begging.
Yaya Toure, Balotelli and Dzeko all tried their luck from distance but didn't hit the target.
Napoli had clearly set their stall out to counter and on one such raid Ezequiel Lavezzi skipped around Nigel De Jong and crossed for the unmarked Marek Hamsik, who played despite his pregnant wife having been car-jacked at gun-point in the morning, but his header went straight at Joe Hart.
Lavezzi played a quick one-two with Cavani but 'Pocho' then shot powerfully wide.
Switzerland midfielder Gokhan Inler tried his luck from long-range but Hart tipped it over.
Lavezzi's corner on 17 minutes was flicked on by Cavani and then came off both Aleksandar Kolarov and Hart's knee before sneaking in at the near post for a soft goal.
The San Paolo was rocking and Cavani fired just wide on another swift counter.
City kept their nerve and continued to dominate possession with David Silva and Balotelli both shooting into Morgan De Sanctis's arms.
The equaliser came on 33 minutes after some shoddy defending.
Salvatore Aronica's poor clearance from Kolarov's cross went straight to Silva and although De Sanctis pushed out his cross-shot, Balotelli was in the right place to tap home.
Cavani had a whack from distance that went well over before Kolarov capped a slick City move with a shot that De Sanctis smothered.
Napoli needed only four minutes to go back in front after the break as Andrea Dossena got down the left and picked out Cavani to shoot home under Hart and this time there were no doubts it was his.
The hosts had their tails up and Joleon Lescott had to hack a Hamsik shot off the line.
Napoli were content to sit back and hit City on the counter and they almost scored a third when Vincent Kompany's slip let in Lavezzi but Hart stood tall to block his shot.
And the hosts went even closer after a mistake by Kolarov let in Hamsik but although his shot beat Hart, it came back off the post and City survived, just, again.
Chances were coming thick and fast, Toure put Balotelli in behind the Napoli defence but De Sanctis saved his shot and Christian Maggio went through one-on-one with Hart who stood up bravely to block.
A brilliant move between Silva and substitute Samir Nasri then teed up Balotelli, who headed over.