Chievo got off to a flying start when Nicola Rigoni put them in front inside two minutes but Gonzalo Higuain equalised four minutes later.
Vlad Chiriches then gave Partenopei a half-time lead and Jose Callejon put the game out of reach in the 70th minute to move Maurizio Sarri's side level on points with Juve.
In the midst of their UEFA Europa League exit, the home side had failed to register a Serie A win in their last three games and were behind in the second minute after former Tottenham Hotspur defender Chiriches, who replaced the suspended Raul Albiol in the starting line-up, gave the ball away cheaply to leave Rigoni clean through on goal to slot past Pepe Reina.
Napoli would respond immediately, however, as Higuain tapped in Faouzi Ghoulam's cross from the left wing to take his Serie A tally to 26 goals for the season.
Chiriches would redeem himself in the 38th minute when he produced a powerful header from Jorginho's cross, leaving Albano Bizzarri stranded in the Chievo goal.
The hosts pushed forward and got their third with 20 minutes to go. Allan was found with acres of space on the right wing before his firm first-time pass met the surging run of Callejon.
The win keeps Napoli's chances of winning their first Scudetto since 1990 alive, while Chievo are 10th.
First-half goals from Roberto Soriano, Antonio Cassano and Lazaros Christodoulopoulos secured a 3-0 win for Sampdoria against Serie A's bottom side Hellas Verona.
Verona need a miracle to save them from relegation as they sit nine points from safety and it took just six minutes for the travelling side to break through their defence when Soriano hit in a rebound from Pierluigi Gollini's save.
Only five minutes later Cassano doubled Sampdoria's lead after calmly going round Gollini and Verona's fate was sealed on the half-hour mark when Cassano's pass found Christodoulopoulos who slotted home.
Verona were stronger in the second half but an impressive defensive performance from Sampdoria ensured there was to be no comeback.
