- Giacomo Raspadori (90'+3')
Juventus, who returned to the top four when their 15-point deduction over the club's transfer dealings was scrapped on Thursday pending a new hearing, remain third on 59 points, two behind second-placed Lazio who lost against Torino on Saturday.
A goalless first half saw defensive Juventus allowing Napoli to enjoy the lion's share of possession, awaiting chances to counter-attack. The approach did not result in many chances for either side and Juve managed only three shots on target.
The game sprung to life with 20 minutes left when Napoli came close to taking the lead through striker Victor Osimhen who fired inches wide of the post.
A minute later Osimhen connected with a corner but headed the ball into the arms of Szczesny and soon after the this season's Serie A top scorer sent the ball narrowly over the bar.
Juve, clearly fired up, thought they had taken the lead with a stunning solo effort by Angel Di Maria in the 82nd minute only to see it cancelled out after a VAR check for Arkadiusz Milik's tackle on Napoli midfielder Stanislav Lobotka in the build up.
Napoli then sealed their eighth away league win in a row through Raspadori, who beat Szczesny with a first-time finish following a beautiful lofted cross by midfielder Eljif Elmas.
Juventus have suffered their first three-game losing streak in Serie A since 2011 after a 1-0 loss to Sassuolo saw them fall to consecutive league defeats for the first time this term. They are winless in five of their last six games in all competitions.
- Michael Fabbri