Juventus are yet to register a win this the Serie A this season, as Napoli came from behind to inflict defeat on the Old Lady in their first game since Cristiano Ronaldo left for Manchester United.
Ronaldo, who helped Juventus win Serie A twice in three seasons, rejoined United on transfer deadline day and scored twice in the second debut for the Red Devils on Saturday.
With Ronaldo out of the picture, Spanish striker Alvaro Morata gave Juve an early lead.
Allegri’s men looked like they would capitalize on the good start and get something out of the game, but second-half goals from Matteo Politano and Kalidou Koulibaly gave Napoli a comeback victory.
Juventus, who came fourth in 2020-21, have only picked up one point from their opening three Serie A matches, losing two and drawing one.