Wissam Ben Yedder hit a hat trick on Saturday night as Monaco came from 2-0 down to beat Brest 4-2 and move up to second in Ligue 1.
Goals from Jean-Kevin Duverne and Mohamed Youcef Belaili within 25 minutes put the visitors in the driving seat at the Stade Louis II.
But Ben Yedder halved the deficit from the penalty spot on the stroke of half-time.
The Monaco skipper levelled just after the pause and added his third on 51 minutes.
Kevin Volland completed the comeback 19 minutes from time.
Monaco's ninth straight victory – coupled with Marseille's 2-0 defeat at Rennes allowed Philippe Clément's side to rise on goal difference one place into the berth for the group stages next season's Champions League.
"We're obviously happy with the way we managed to come and play," said Ben Yedder.
"We've got to back this up with a win next week. But we're calm. We know what we can do and we've just got to go out and do it."
Marseille's loss at Rennes - who moved into fourth and the slot for the Europa League - means they must beat Strasbourg next Saturday to reclaim second place and hope that Monaco fail to secure victory at Lens who have an outside chance to finishing in fifth - which leads to the Europa Conference League.
At the other end of the food chain, Bordeaux were relegated following a 0-0 draw with Lorient and Saint-Etienne lost for the 20th time this season.
They went down 2-1 at home to Reims and dropped to 19th while Metz, who had occupied the second automatic relegation slot, beat Angers 1-0 to move above Saint-Etienne on goal difference into 18th and the relegation play-off spot with a team from Ligue 2.
Next Saturday, Metz play at champions Paris Saint-Germain while Saint-Etienne will take on Coupe de France winners Nantes. Whoever emerges with the best result from those clashes will get a chance to play for their Ligue 1 survival.