With only one win in their last 10 matches away from home (D3, L6), Monaco started on the front foot and took the game to the hosts but couldn’t find a way to test Marco Bizot in a frantic first half littered with fouls and strong challenges.
Brest eventually started to grow into the contest and had the first real chance when Philipp Kohn weakly punched the ball towards the edge of the area where Mahdi Camara lay in wait, but the Swiss goalkeeper atoned by making the save.
It looked like the first period would end goalless until a defensive mix-up just before half-time gifted the home side the lead.
It looked like Kohn was well-placed to save a shot from Abdallah Sima, however, he was impeded by Thilo Kehrer, who attempted to block, and the ball looped in the air before agonisingly nestling in the back of the net, going down as an own goal against Kohn.
Adi Hutter responded with a double change after the interval, and, similarly to the first half, they came out the traps quickly without creating anything clear-cut.
That changed just after the hour mark when a VAR review penalised Kenny Lala for a handball from point-blank range in the box, and Denis Zakaria stepped up to slam the penalty past Bizot.
A sense of injustice appeared to inspire the hosts as they seized control of the game in the aftermath of the equaliser, but they had to be wary of the visitors on the break, with Eliesse Ben Seghir forcing a fine fingertip save.
Just when it looked like both sides would have to settle for a point, Camara struck a winner deep into stoppage time when his hopeful shot from distance somehow found its way past Kohn to send the home fans wild.
The victory could prove to be huge for Brest’s European hopes as they move within three points of the top six, while Monaco remain in second but sit only one point ahead of Marseille, having also played a game more.
Flashscore Man of the Match: Brendan Chardonnet (Brest)