Last season's Serie A runners-up Napoli suffered a 2-1 defeat at home to Como on Sunday, with all three goals coming in an entertaining opening half.
Como have Champions League football to look forward to this season after a fourth-placed finish brought the club European qualification for the first time, and in Naples, Cesc Fabregas' side showed last season's campaign was no flash in the pan.
Assane Diao looked the most threatening player in the opening stages, sending dangerous crosses into the Napoli area, and the Como winger was instrumental in the visitors' 17th-minute opening goal.
Diao went past Mathias Olivera on the right wing and played a pass across to Martin Baturina whose shot on the turn from close to the penalty spot found the bottom corner of the net.
Noa Lang missed an excellent chance to equalise, sending a header over from inside the six-yard box, before Napoli drew level on the half-hour mark.
Rasmus Hojlund collected a pass on the edge of the area, rolled the ball away from defender Jacobo Ramon to make room for the shot which he drilled low into the far corner, but Como were back in front four minutes later when Napoli were caught napping at the back.
Andre Anguissa underhit a pass back to Amir Rrahmani in his own box, allowing Baturina to nick the ball away. It fell to Tasos Douvikas and Como's top scorer last season netted his second goal of this campaign.
Massimiliano Allegri was rescued by his bench last weekend, when late goals from substitutes earned a win at Genoa, and the Napoli boss made a triple-change 10 minutes after the break, but Como held on to take all three points.
Como are on four points, two behind leaders AC Milan and Juventus who are on maximum points after two games. Napoli have three points and champions Inter Milan can join the top two when they face Cagliari away later on Sunday.
