These followers shall be hoping Juve would possibly drop factors of their remaining video games, particularly as they should play away at third-place Roma and fifth-place Inter Milan.
Maurizio Sarri's side pushed forward with numerous chances compared to Juventus who, apart from a Miralem Pjanic free kick hitting the post, had little to show.
Napoli captain Marek Hamsik threatened twice to break the deadlock while Lorenzo Insigne had a goal disallowed for offside in the first half, before substitute Piotr Zielinski's late snapshot was cleared by Gianluigi Buffon.
"We have always believed in the title and now we believe in it more than ever", Koulibaly said.
Manchester City "Are From Another Planet" - Carlos Carvalhal
Each of these could draw a Football Association charge but Guardiola , understandably, was not concerned. Such was the gulf in class that City had 83 percent possession and completed 943 passes.
You have to go back to March 2015 to find the last time Napoli lost to any of those teams and they have already won 10 points against the quartet this season, with only Fiorentina avoiding defeat.
"Juventus are still ahead, we just have to think about the next game". This win here tonight is hugely satisfying for us and for them. Napoli's most hard game left may be their next away trip to Fiorentina, after which they face Torino, Sampdoria and Crotone.
Elsewhere, Lazio and Inter kept their push for Champions League football alive on Sunday.
The Partenopei looked set to be forced to settle for a draw that would leave them four points behind the reigning champions after a tense contest in Turin on Sunday.
Fans also lit fireworks across the city as the final whistle went and celebrated in public squares after defender Kalidou Koulibaly had headed in the winning goal in the last minute of the game against Juve.