The top three in Ligue 1 are all in action on different days this weekend, meaning leaders Paris St Germain could be under severe pressure by the time they visit fourth-placed St Etienne on Sunday.
Third-placed Marseille get the programme under way with Friday night's home tie with Ajaccio, where a win will take them level on points with Lyon in second, albeit with a significantly inferior goal difference.
Lyon then travel to Bastia on Saturday knowing a win will take them to within a point of PSG, whose tough away clash with St Etienne is Sunday's late game.
Both St Etienne and Nice are just two points behind Marseille in the battle for Champions League qualification, and OM midfielder Lucas Mendes is taking nothing for granted.
"Obviously I'm looking ahead but I haven't forgotten about St Etienne and Nice," the Brazilian said on om.net. "The slightest mistake on our behalf and these other sides could steal our third place.
"There are no easy matches. Several times we thought we were going to win and we have lost. But I do prefer to look ahead rather than over my shoulder."
Ajaccio have won only once in 12 visits to the Stade Velodrome, the last coming almost eight years ago.
If Marseille slip up, St Etienne will fancy their chances of capitalising.
Brazilian striker Brandao could return for Les Verts after missing the 2-2 draw with Rennes with a thigh strain.
The nine-goal striker has returned to training and could figure in coach Christophe Galtier's squad as they look to maintain their unbeaten run in 2013.
PSG will be without their own Brazilian star Lucas Moura, but there was still some good news on the injury front.
Moura was forced off in the 55th minute of PSG's 2-1 win over Nancy last weekend, amid concerns that he had sustained ligament damage in his left ankle.
However, further examination showed that the winger had suffered a simple sprain and should be back in action in a fortnight's time.
Elsewhere this weekend, Sochaux and Reims will try to climb away from the relegation zone with home games against Valenciennes and Rennes respectively, while Evian - who are also on 27 points - face a tough trip to Lille.
Fellow strugglers Troyes travel to Montpellier and Lorient are at home to Brest, while on Sunday bottom side Nancy entertain Nice in the early game and Toulouse then take on Bordeaux.