The treble was his second of the season and takes his tally so far this term to ten goals in six games in all competitions and eight in four in Serie A.
The 23-year-old opened the scoring in the first half before bagging another two after the break as he moved on to 52 goals in 100 games for Juve.
Speaking after the game, Juve boss Allegri heaped praise on the youngster, saying that he is turning into an 'extraordinary player.'
Allegri told Juve's club website: 'He still has room for improvement, but at times he's just unplayable. He's turning into an extraordinary player.'
Sassuolo manager Cristian Bucchi also praised Dybala's performance, calling him a 'great champion.'
Bucchi su #SassuoloJuve: «Buona prova, ho visto segnali incoraggianti.Dybala è un grande campione. Da mercoledì inizia il nostro campionato» pic.twitter.com/C45gGj1mEG
— U.S. Sassuolo (@SassuoloUS) 17 de septiembre de 2017