Eight minutes from time Szczesny inadvertently parried a rebound into the path of Andrea Pinamont, who headed home to make it 3-2 to Sassuolo.
Juve had first equalised after 21 minutes when Sassuolo defender Matias Vina inadvertently poked the ball into his own net from close range while attempting to clear a cross.
Sassuolo had a chance to make it 3-1 around the hour mark, but Lauriente fired over the bar from close range.
Chiesa then levelled for the visitors in the 78th with a deflected shot before Sassuolo struck twice to take the points.
In the post-match press conference, Allegri reaffirmed Szczesny as his starting goalkeeper but hinted at unspecified changes for the upcoming match.
Persons:
Sassuolo's Matias Vina, Alberto Lingria, Wojciech Szczesny's, Armand Lauriente's, Szczesny, Andrea Pinamont, Federico Gatti, Massimiliano Allegri, DAZN, Juve, Matias Vina, Domenico Berardi, Federico Chiesa, Sassuolo, Lauriente, Chiesa, Allegri, It’s, Tommy Lund, Ken Ferris, Clare Fallon
Organizations:
Soccer Football, Sassuolo, Juventus, Mapei, Tricolore, Reggio, Weston, Serie, Polish, Inter Milan, Empoli, Milan, Hellas Verona, Juve, Lecce, Thomson
Locations:
Reggio Emilia, Italy, Gdansk