Saliba, who has been reduced to playing youth matches for the Gunners so far this season after being frozen out of the first-team squad, started the contest but his lack of match action was apparent from the off.
The former St Etienne defender was booked just 11 minutes into the contest, and things didn't get any better for the 19-year-old from there on.
Brest struck twice within the space of five minutes in the middle of the first half, former Huddersfield Town man Steve Mounie pouncing for the first, and Franck Honorat struck the second, as the Nice team-mates looked at each other in bemusement.
🗝️ Key Stats
William Saliba match stats
|Pass Completion %||91%|