Matthijs De Ligt, who tested positive for Coronavirus, had his spot taken by Merih Demiral as Weston McKennie and Arthur Melo completed Juve's changes from the win over AC Milan.
Sassuolo showcased their intentions early on when Gian Marco Ferrari dragged a close-range strike beyond the far corner, while a looping header from Cristiano Ronaldo went over the top.
McKennie's evening ended after a subsequent knock made him unable to carry on playing towards the midway point and such saw Ramsey occupying his spot.
Another injury forced substitution propped up for Juve five minutes to halftime when Paulo Dybala made way for Swedish international Dejan Kulusevski.
Sassuolo played the rest of the match with ten players when Pedro Obiang saw red for a lunge on Federico Chiesa on 45 minutes following intervention from the Video Assistant Referee (VAR).
Kulusevski should've given Juventus the lead deep in added time from a loose pass in the area but with the goal gaping, scooped over the top.
Juventus finally broke the deadlock five minutes into the second half when a first-time strike outside the area from Danilo nestled the bottom-corner following a loose clearance.
Gregoire Defrel pulled the visitors level on 58 minutes after he controlled a low pass from Obiang before rattling the far corner with an instinctive strike.
Juventus missed a golden chance to go back in front minutes later when a snap shot in the area from Chiesa struck the outside post before Andrea Consigli denied Ronaldo from close-range.
Nevertheless, the lead was regained in the final eight minutes as Ramsey popped at the back-post to help Gianluca Frabotta's ball from the left-side into an unguarded net.
Ronaldo completed the victory with the last kick of the game after he ran in from the right to slot into the far corner, as it finished 3-1 to the defending champions.