The 27-year-old scored the only goal of the game after just four minutes, guiding a first-time shot from the edge of the box past David Raya in the Arsenal goal.
Dembele was then replaced by Bradley Barcola in the 70th minute after pulling up with what appeared to be a hamstring injury.
Journalist Fabrice Hawkins revealed Dembele was absent from training on Thursday and will likely miss PSG’s Ligue 1 game with Strasbourg on Saturday.
PSG have since released an official update regarding his fitness, which could spell danger for Mikel Arteta’s side ahead of their Champions League semi-final second leg next week.
"Ousmane Dembele has strained his right hamstring. His condition is progressing well. A further assessment will be carried out shortly," the medical report read.