Lille condemn Sampaoli to defeat on Rennes debut
Kosovo international Edon Zhegrova struck right before half-time as Lille extended their unbeaten run to eight games to stay a point behind third-placed Marseille.
Rennes failed to create any proper chances and slid to a seventh defeat in 12 matches.
Sampaoli, a 2015 Copa America winner with Chile who spent 16 months at Marseille between 2021 and 2022, will hope to lead Rennes away from trouble with games to come against Saint-Etienne, Nantes and Angers before the new year.