The Borussia Dortmund star acknowledges that his side are struggling with injuries but is still hoping to triumph at the Velodrome to seal Champions League progression
The French giants dispensed with the services of coach Elie Baup following Friday's 1-0 loss to Nantes and have failed to take a point from any of their five Champions League group games thus far.
Jurgen Klopp's men need victory at Stade Velodrome to guarantee progression to the knockout stages of the competition and the Gabon international is hoping to heap more misery on l'OM.
"Marseille are in a bad phase. It is up to us to take advantage of this," he was quoted as saying by Uefa.com.
"This will be difficult but we are confident and determined. We are motivated to play and qualify. This game is crucial in the qualifying run.
"Despite the injuries I trust our defence and I am sure tomorrow will be a good game. Our game is an attacking one, we play with a lot of intensity, this is our strength."
BVB overcame Marseille 3-0 on matchday 2 of the competition over in Germany, with Robert Lewandowski scoring twice and Marco Reus netting the other goal.