The forward scored the opening goal, after a lengthy VAR review of a Matthieu Udol handball, with a penalty that took his league tally to 14 for the season.
But the former Celtic attacker limped off and was replaced by Amine Gouiri in added time.
Lyon host Juventus on Wednesday in the first leg of the Round of 16 of the Champions League and Garcia said of Dembélé: "He's got nothing, there are no worries there."
The OL boss also said Jason Denayer will be fit to face the Serie A giants.
Garcia said: "We didn't concede chances and we were well set up in the new system with three defenders."
"We must still improve in certain areas, notably in the precision of our crossing. Bruno's integration went well and so did Léo Dubois' return."
"The system allowed them to be at ease. We won by two goals and that's good as we were up against a valiant, physical team. We can now focus on the Champions League."