Napoli produced a sensational performance to beat Juventus and go 10 points clear in their bid for a first Serie A title since 1990.
Juventus had won eight games in a row without conceding, but that record was ruthlessly ended at the Diego Armando Maradona stadium.
Victor Osimhen scored two goals with Khvicha Kvaratskhelia, Amir Rrahmani and Elif Elmas also on target.
Angel di Maria answered for Juventus, who thus slipped to third place.
Osimhen opened the scoring for Napoli and then provided the pass for Kvaratskhelia to double their lead, but Di Maria fired back before the break.
Rrahmani restored the hosts’ two-goal lead 10 minutes after half-time and from there Luciano Spalletti’s side were rampant.
Georgian star Kvaratskhelia picked out Osimhen with a superb cross and the Nigerian striker headed his 12th Serie A goal this season.
Elmas’ deflected effort completed the scoring as Juventus conceded five goals in a match in the competition for the first time since May 1993.
Massimiliano Allegri’s side had conceded just seven in the top flight this season before and sat third, level on points with second-placed AC Milan.
But it was a breathtaking display in Napoli, which underlines the hosts’ credentials for a first Serie A title since Maradona was in their ranks 33 years ago.