Napoli have missed the chance to keep the pressure on Lazio after Catania battled back from two goals down to salvage a 2-2 draw.
The hosts laboured during the first half and had to wait until the hour mark before finally breaching the deadlock.
Blerim Dzemaili struck a fine right-footed effort from outside the area past a helpless Juan Pablo Carrizo in goal.
Cavani then made it 2-0 with a shot from an acute angle six minutes later, having hit the post just moments earlier.
Hope was restored for the visitors in the 7th minute, when Nicolas Spolli halved the deficit.
The comeback was complete when Davide Lanzafame levelled matters five minutes from the final whistle.
Napoli will no doubt see the result as a missed opportunity to push their claim for a spot in next season's Champions League.