PARIS (AFP) - Swiss striker Alexander Frei returned to haunt Marseille on when he scored the winner in Rennes' 1-0 win which sent the French giants tumbling into midtable and their fans calling for the resignation of president Christophe Bouchet.
Frei, who hit a hat-trick in the corresponding fixture last season, rose above the Marseille defence to head home the decisive strike from a corner after 58 minutes past Fabien Barthez in goal.
It was Frei's fifth goal of the season and was reward for his side's complete domination of the second half.
The defeat leaves Marseille in 10th place in the table, five points behind leaders and defending champions Lyon, and their plight could worsen later Wednesday when the remainder of the midweek programme is completed.
Marseille had squandered an early chance to score when they were awarded a penalty in the 15th minute but Steve Marlet's spot-kick was well-saved by Andreas Isaksson.
The penalty had been given when Etienne Didot had handled in the area.
Habib Beye also came close for Marseille in the 35th minute but again Isaksson was alert to keep out the header.
Rennes dominated the second half and were well worth their lead although they still needed their Swedish goalkeeper to come to their rescue in the 69th minute by again denying Marlet.