Serena Williams suffered another French Open defeat on Friday when she and Bob Bryan, who she plans to play with at the Olympics, lost in the first round of the mixed doubles.

The Americans were defeated 7-5 3-6 10-6 by Argentina’s Gisela Dulko and Eduardo Schwank.

Serena slumped to a first ever first round Grand Slam singles defeat on Tuesday when she squandered a set and 5-1 lead in the second set tiebreaker to lose to France’s Virginie Razzano.