Danish forward Kasper Dolberg scored twice as Nice avenged their midweek French Cup exit to Lyon with a 2-1 victory on Sunday in a game that saw both sides finish with 10 men, while second-placed Marseille were held to a goalless draw by Bordeaux.
Lyon qualified for the quarter-finals on Thursday following a last-gasp 2-1 victory, but the visitors had defender Fernando Marcal sent off on 22 minutes for a foul as the last defender.
Nice grabbed the lead through Dolberg in the 33rd minute after Ciprian Tatarusanu failed to hold a deflected Pierre Lees-Melou strike, allowing the Dane to convert the rebound.
Lyon levelled before half-time when Karl Toko Ekambi turned home from point-blank range after a jinking run and shot from Houssem Aouar.
The hosts were themselves left to play a man down after Adam Ounas was dismissed for his role in a scuffle involving Lyon centre-back Marcelo and Nice's Alexis Claude-Maurice.
Dolberg hit the winner just past the hour when he poked in a driven low cross from Hicham Boudaoui as Nice extended their unbeaten league run to six games.
Patrick Vieira's side climbed level with six-placed Lyon on 32 points, eight adrift of Rennes in the final Champions League qualifying spot.
Andre Villas-Boas' Marseille slipped 12 points behind leaders Paris Saint-Germain after being held to a second straight Ligue 1 stalemate at Bordeaux.
The visitors had chances to snatch victory late on, with Bordeaux goalkeeper Benoit Costil denying Nemanja Radonjic with an excellent save.
Bordeaux centre-back Pablo had a goal ruled out for handball in the first half of a largely uneventful encounter.
Marseille lead third-placed Rennes by three points in the race for automatic Champions League qualification, with Lille six points further adrift in fourth.
Marseille are unbeaten in 14 games in all competitions and have not lost since October.
PSG extended their advantage by thrashing Montpellier 5-0 on Saturday.