Marseille boss Elie Baup has ordered his players to tighten up as they attempt to rekindle their season at home to Valenciennes.
OM have won just one of their last five Ligue 1 games, although they emerged from last weekend's trip to lowly Evian with a point despite playing the final 15 minutes of a 1-1 draw with just nine men following the dismissals of Kassim Abdallah and Jordan Ayew.
As a result, they have slipped eight points adrift of leaders Paris St Germain and two of second-placed Lyon, and Baup knows they cannot afford to concede goals in the numbers they have - nine in those five matches - if they are to get back on track.
He told the club's official website, www.om.net: ``We need to have the desire to build the game, keep pressing, but with high security.
``We must find answers. It is not normal to concede as many goals.''
Valenciennes, who currently sit in 11th place in the table, will arrive at the Stade Velodrome boasting an enviable record against Marseille, to whom they have not lost in their last five encounters.
Indeed, they defeated Baup's men 4-1 at the Stade du Hainhaut in September with an Anthony Le Tallec double either side of half-time doing much of the damage.
Coach Daniel Sanchez told the club's official website, www.va-fc.com: ``Marseille will certainly not forget the first game. It was a good game for us, more difficult for them.
``It still serves as motivation for the coach to activate the levers, but they will be looking for revenge.
``In recent times, Marseille's results have see-sawed. This team is capable of doing good things, but also things a little rougher.
``Marseille need to react. We know we must be wary of this.''
Valenciennes head into the game having ended a run of four games without a victory by beating Brest 2-1 at home last Saturday.
Marseille will be without Abdallah and Ayew, who are suspended as a result of their red cards at Evian, but Joey Barton is available after serving the one-match man he collected for his sending-off in the 1-0 home defeat by Nancy during the previous weekend.