Lille has seen its five-point lead in the French league wiped out over the last two matches, just as defending champion Marseille's title bid is gathering momentum.
Lille tops the league only on goal difference from Rennes, Marseille is only one point behind in third place and Paris Saint-Germain is just two points adrift in fourth spot.
Lille travels to Marseille on Sunday and Lille midfielder Florent Balmont thinks his team will need plenty of grit and determination to get a result at Stade Velodrome.
"We'll need to be very strong because we're going to suffer a lot over there," Balmont said. "If we get a point there we'll be happy with that because we'll still be in the (title) race."
But Balmont thinks Lille should stick to its trademark attacking game, rather than attempting to battle it out for a point.
"We have the ability to play, but we're also strong defensively," he said. "It won't be easy but we shouldn't be fainthearted about it."
A series of scrappy wins, meanwhile, has left even Marseille fans groaning about the team's dreary style of play.
But if Marseille beats Lille, and Rennes fails to beat Montpellier away on Saturday, coach Didier Deschamps' team will be back in first place for the first time since briefly topping the league in early December.
Marseille's credentials are set to be severely tested, because the following two league games will be away to Rennes and at home to PSG, with a Champions League last-16 return leg at Manchester United sandwiched in between.
"The calendar (fixture list) is drawn up in such a way that we're up against our direct rivals," former France captain Deschamps said. "We'll see come the end of March. We'll have a clearer idea about what we're capable of achieving."
Marseille has won its last four league games, all by a single-goal margin, and has not scored more than twice in any game since thrashing Montpellier 4-0 in November.
But Deschamps has had to contend with injuries to creative players such as strikers Andre-Pierre Gignac and Loic Remy and winger Mathieu Valbuena - all France internationals - throughout the season, getting the best out of his squad through a more pragmatic approach.
While it is not pretty to watch, it is certainly effective. Marseille was six points behind free-scoring Lille heading into the winter break but coach Rudi Garcia's players have looked tired recently, winning only one of the last eight games as they competed on three fronts.
Lille went out of the Europa League to PSV Eindhoven last week and scraped into the semifinals of the French Cup on penalties on Wednesday after drawing 0-0 against Lorient.
Goals have been drying up for Lille's prolific attack, prompting the unexpected slump. Lille led Rennes by five points before a 1-0 defeat away to Montpellier and a 1-1 home draw against Lyon let its rivals back into the race.
"It will be another big game, like a real Champions League match," said Lille winger Eden Hazard, who scored the winning penalty against Lorient on Wednesday night. "I've never won a match at Stade Velodrome before."
Gignac (groin), Remy (sprained ankle) and Valbuena (knee) have all been training under supervision from Marseille's doctor in a bid to be fit for Sunday's match. Remy says he is "confident" of playing.
In Saturday's other games, it's: Caen vs. Saint-Etienne; Lorient vs. Nancy; Nice vs. Lens; Toulouse vs. Sochaux; Valenciennes vs. Monaco; and Auxerre vs. PSG.
Fifth-place Lyon hosts last-place Arles-Avignon, and Brest faces Bordeaux in Sunday's other matches.
Bordeaux coach Jean Tigana agreed this week to remain in charge until at least the end of the season, after the club's directors persuaded him to stay.
