MILAN: Juventus fell to a surprise 3-2 defeat at Sampdoria, which maintained its perfect home record in Serie A on Sunday.
Duvan Zapata, Lucas Torreira and Gian Marco Ferrari put Sampdoria 3-0 up in the second half before Juventus threatened an astonishing stoppage-time comeback with a penalty from Gonzalo Higuain and a strike from Paulo Dybala.
It will be a blow to Juve's confidence ahead of Wedesday's Champions League match against Barcelona.
Juventus is four points behind leader Napoli, which beat AC Milan 2-1 on Saturday. The Bianconeri could be overtaken by Inter Milan, which is a point behind and hosts Atalanta later.
Sampdoria, which has played a match less than most other teams, moved five points behind Juventus.
Juventus was without defender Andrea Barzagli and goalkeeper Gianluigi Buffon, who were recovering from the disappointment of Italy's failure to qualify for the World Cup and Sampdoria made the most of their absences to expose the Bianconeri defensively.
Samp broke the deadlock six minutes into the second half when a poor clearance by Federico Bernardeschi on Fabio Quagliarella's cross fell straight to Zapata. He leapt above Stephan Lichtsteiner to send a looping header past Wojciech Szczesny.
Juventus upped the pressure but was stifled by a solid Sampdoria side, which doubled its lead in the 71st with a fine strike from Torreira from just outside the area into the bottom left corner.
It got worse for Juve eight minutes later. The defense should have dealt better with a cut-back from former Juventus forward Quagliarella but Ferrari beat Sami Khedira to tap in from close range.
Juventus had penalty appeals turned down at the end of the first half but it was awarded a spot kick at the end of the second when Douglas Costa was tripped by Ivan Strinic for a last-gasp penalty. Higuain converted in the first minute of stoppage time but it seemed to be too little, too late.
Dybala reduced the deficit still further moments later when he ran down the right flank before cutting inside and placing the ball into the bottom right corner. But Juventus didn't have time to get the equalizer, with Higuain flagged offside in the last piece of action.