Sarr gave the hosts an early lead within the first 10 minutes of the encounter courtesy of an assist from Clement Grenier.
He curled a right-footed shot from outside the penalty area to the top corner to register his fifth league goal of the season.
Ismaila Sarr <3 pic.twitter.com/9bx0TJ0XfR— KierownikWodopoju (@BoyBetterKnown_) December 2, 2018
The 20-year-old's goal gave Sabri Lamouchi's men hopes of grabbing maximum points after back-to-back draws in their last two league fixtures [vs. Nantes and Montpellier] but a brace from Jonas Martin and efforts from Adrien Thomasson and Pablo Martinez denied them
Sarr was in action for the entire duration of the game while South Africa marksman Lebo Mothiba was on parade for 71 minutes for the visitors.
The result saw Rennes drop to 14th in the league standings with 17 points from 15 matches.