Second-placed OM, who take on second-from-bottom Stade Brest on Saturday, have not conceded a goal in their last five Ligue 1 outings, thanks to sterling performances by centre backs Lucas Mendes and Nicolas N'Koulou, while keeper Steve Mandanda produced a world-class performance in the 0-0 draw at Lille last Sunday.
The club have Andre-Pierre Gignac to thank for the goals that gave them their last two wins but have gained little from the presence of Andre Ayew in the starting line up, with the Ghana striker unable to score in 10 weeks.
Younger brother Jordan has also been missing in action and has not scored since January 26.
Marseille are clinging on to second place, two points ahead of Olympique Lyon and four ahead of both St Etienne and Nice with six matches left.
"There is a collective momentum, a desire not to concede a goal, to stick together," coach Elie Baup told the club's website (www.om.net).
"It shows that we are not ready to let our place on the podium slip. We are going to continue like this."
Marseille will be comforted by the fact that Brest have the worst attack in Ligue 1, having scored 29 goals this season.
Runaway leaders Paris St Germain, who lead Marseille by nine points on 67, take on Champions League hopefuls Nice on Sunday looking to make amends for their elimination in the French Cup quarter-finals by Evian Thonon Gaillard on Wednesday.
Fifth-placed Nice will be without teenage striker Neal Maupay who has been ruled out until the end of the season with a knee injury.
"It is a big blow for him and for us because we need everyone," said coach Claude Puel, who will also be without suspended striker Eric Bautheac.
On Friday, third-placed Lyon travel to Montpellier who will surrender their title at the end of the season but still have an outside chance of clinching a Europa League spot.
Lyon are back in the mix for a direct qualifying spot for the Champions League after a 3-1 win over Toulouse ended a three-game losing streak last weekend.
"We need to confirm this against Montpellier. The Toulouse win gave us something to cheer about after a very difficult period," Argentine striker Lisandro Lopez, who has had a below-par season, told reporters.