Nice battled back from a goal down to win 2-1 at Clermont on Sunday and move second in Ligue 1, after Lens were thrashed by Brest.
Christophe Galtier's side are now 11 points behind league leaders Paris Saint-Germain as they bid to qualify for the Champions League.
The visitors were facing a second straight defeat when Florent Ogier gave promoted Clermont a 17th-minute lead.
But Nice were rescued by in-form forward Amine Gouiri's late double as the France Under-21 international scored in the 77th and 82nd minutes to take his tally of league goals this season to eight.
Nice, bankrolled by British billionaire Jim Ratcliffe's Ineos company, are hoping to reach Europe's premier club competition for the first time since the 1959-60 European Cup.
They lost in the qualifying play-off four years ago.
Despite a one-point deduction earlier this term due to crowd trouble, Nice now have a two-point lead over fourth-placed Lens in the race for the top three.
However, Marseille can draw level on points with Galtier's men when they visit Lyon later on Sunday.
Rennes sit third after extending their unbeaten run to 11 matches in all competitions with a 2-0 win over Montpellier on Saturday.
Lens, who were second in the table at the start of the weekend, slipped to a surprise 4-0 hammering at struggling Brest.
Franck Haise's Lens, only in their second season back in the French top flight, were looking to move back within 10 points of PSG.
But a nightmare first half put paid to any hopes of that, as Steve Mounie gave Brest a third-minute lead before goals from Brendan Chardonnet and the in-form Romain Faivre made it three at the break.
Lens' miserable afternoon was completed in the second half as Jeremy Le Douaron added a fourth for the hosts in the 69th minute and the away side saw substitute Arnaud Kalimuendo sent off.
On Saturday, Lionel Messi scored his first Ligue 1 goal as PSG stretched further clear with a 3-1 victory against Nantes.