Napoli postponed Juventus's march to the Serie A title and consigned Chievo to relegation with a 3-1 win at the Stadio Bentegodi on Sunday.
Carlo Ancelotti's side needed a victory to ensure that the Turin club, who lost 2-1 at SPAL on Saturday, would not wrap up their eighth consecutive league championship with a record six games to spare.
Two goals from Kalidou Koulibaly either side of an Arkadiusz Milik strike confirmed Chievo's demotion despite Bostjan Cesar's late consolation, after a miserable season in which the Verona club have recorded just one win in 32 games.
The result leaves second-placed Napoli on 67 points, 17 behind runaway leaders Juventus on 84.
However, Juve can secure the title by avoiding defeat at home to Fiorentina next weekend.
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