كتب : Omar AbdelAziz
Despite being ahead thanks to a 46th minute striker from Alessandro Del Piero, Juve failed to overcome the home side, who managed to fight back and win the game.
Three minutes after Del Piero's opener, Uruguayan midfielder Walter Gargano equalized for Napoli, before Maurizio Domizzi converted in two spot kicks in the 62nd and 70th minutes to round off the victory.
Juve remain second with 17 points, while Napoli, who produced a superb display last week as well in a thrilling 4-4 draw at Roma, jump to fifth with 15 points.
Earlier on Saturday, Torino eased to 2-0 victory over Cagliari, with goals from Alessandro Rosina and Michele Ferri (own goal).