The defending champions, seeking a seventh successive Scudetto, went into the game four points behind Napoli.
But they took the lead after just 12 minutes at the Stadio San Paolo, Gonzalo Higuain's sixth league goal in five games proving the decisive blow.
Higuain's composed finish inside Pepe Reina's left-hand post ensured that Juve have now found the net in each of their last 44 Serie A games, setting a new record in the competition.
While the 29-year-old Argentine deserves plenty of praise for his efforts, 24-year-old Paulo Dybala deserves some credit as well, laying on another assist for his countryman at club level.
Of Dybala's last 11 assists in Serie A play, seven have been for Higuain goals, making them one of the most feared duos in the league.
And, while one streak for Juventus was continued, one for Napoli came to an end.
The league leaders had gone 26 matches unbeaten before Friday's contest, and have now lost just three times in 45 Serie A games, with two of those losses coming against Juve.