Monaco boosted its chances of staying up and slowed down Lille's bid for an automatic Champions League place with a 1-0 away win on Friday.
Brazilian striker Carlos Vinicius pounced in the last minute to move Monaco up to 16th place in the French league and keep Lille under pressure in the fight for second.
Third-place Lyon can close the gap to four points with a home win against seventh-place Montpellier on Sunday, after which both sides have nine games left.
In Friday's other game, eighth-place Nice conceded a last-gasp equalizer in a 1-1 home draw with 14th-place Toulouse.
As so often this season, Nice played without a recognized center forward and midfielder Wylan Cyprien opened the scoring midway through the first half with a free kick from 30 meters (33 yards) out. Striker Firmin Mubele equalized in the 89th minute for Toulouse, which moved further away from the danger zone.
Meanwhile, runaway league leader Paris Saint-Germain remains 17 points clear of Lille despite playing two games less, and is even closer to another title after Lille's stumble.
PSG hosts bitter rival Marseille on Sunday, with only the title and the French Cup to focus on following its surprise elimination from the Champions League.
Marseille has found form since the arrival of striker Mario Balotelli from Nice. He has netted five times in seven games to help the club into fourth place.