Marseille climbed back into second place in Ligue 1 on Sunday despite being held to a 1-1 draw at fellow Champions League chasers Lille.
Roberto De Zerbi's side moved one point ahead of third-placed Monaco, with Nice, Lille and Strasbourg all one point further behind with two matches remaining.
Runaway leaders Paris Saint-Germain are 19 points clear and already assured of the title.
The top three will qualify for next season's Champions League proper, with fourth securing a spot in the qualifying rounds.
Marseille were the better side in a largely disappointing first half, going close to opening the scoring when Lucas Chevalier made a good save to keep out Michael Murillo's shot.
Chevalier also denied Adrien Rabiot when the France midfielder was through one-on-one early in the second period, but the visitors took the lead in the 57th minute.
Rabiot was played in behind again and this time he squared the ball for Amine Gouiri to tap in his eighth Ligue 1 goal since signing from Rennes on deadline day in January.
But Lille hit back with 15 minutes remaining, courtesy of a gift from Marseille goalkeeper Geronimo Rulli.
The Argentinian miskicked a pass straight to Jonathan David inside the area, who nodded the ball down for Matias Fernandez-Pardo to slot home.
David went close a couple of minutes later as OM threatened to unravel, rifling a long ball into the channel narrowly over the bar.
Marseille pushed for a winner in the dying stages, but Lille held on for what could prove to be a crucial point come the end of the season in a fortnight's time.
LYON SLIP OFF PACE
Earlier, Lyon suffered a blow in their top-four bid as they slumped to a 2-1 home defeat against Lens.
Paulo Fonseca's men remained seventh, outside the European places but only three points behind fourth-placed Nice.
"We'll try to win our next two matches to see where we can get to (in the table), knowing that we have the possibility of getting to where we want to be, but depending on others," said Lyon assistant coach Jorge Maciel, with boss Fonseca serving a nine-month ban for confronting a referee.
Goduine Koyalipou fired Lens into the lead midway through the first half after Lyon failed to clear a corner.
Lyon pressed for an equaliser but struggled to create any clear-cut chances until Georges Mikautadze met Clinton Mata's deep cross with an excellent header into the far corner with 11 minutes remaining.
The Georgia striker has 17 goals and 11 assists in all competitions for Lyon this season despite not always being first-choice.
The visitors snatched all three points when substitute Anass Zaroury hammered a spectacular strike into the top corner from long range in the 85th minute.
Elsewhere, Le Havre gave their hopes of survival a boost with a 2-1 win at Auxerre.
Le Havre, who occupy the relegation play-off spot, are now just one point behind both Angers and Nantes.
Gabon forward Jim Allevinah gave Angers a vital 1-0 victory over Nantes.