Struggling Le Mans came from a goal down to inflict a fifth defeat in six games on Bordeaux as the champions' quest to defend their Ligue 1 title slips further from their reach.
Carlos Henrique put Laurent Blanc's side ahead after seven minutes but the lead lasted just nine minutes when Anthony Le Tallec drove home a powerful shot.
The hosts then went ahead on the stroke of half-time when Mathieu Dossevi took advantage of a mix-up.
Fousseyni Cisse was sent off for a second yellow card with seven minutes left but Bordeaux again slipped to defeat and are now nine points off league leaders Marseille - albeit with a game in hand.
The victory was vital in Le Mans' fight against relegation although they are 10 points off safety.
It had all started so well for Bordeaux when Henrique placed a header into the top corner of the goal.
The hosts were soon back in it when they levelled against the run of play. Sebastian Corchia's corner being turned home by Le Tallec.
Le Mans were grateful to Didier Ovono for keeping the scores level when he made a diving save from Wendel's long-range shot.
The home side went ahead right at the end of the half when Dossevi took advantage of confusion between Benoit Tremolinas and Cedric Carrasso to tap home.
However, they were fortunate when Fernando Cavenaghi's shot went through Ovono's arms and clipped the post before going out.
Cisse picked up his red card following a foul on Henrique but Bordeaux could not take advantage despite Henrique's late header which Ovono collected on the goal line.