This was a mouthwatering warm-up for the big clash later on Saturday when leaders Clermont host second-placed Toulouse.

And yet this match may prove just as important in the long run, with Bordeaux scrum-half Baptiste Serin putting in a ruthless man-of-the-match performance with two conversions and six penalties to lift his team to fifth, seven points from the summit.

Jean-Baptiste Dubie touched down for the visitors after seven minutes and French international prop Jefferson Poirot crossed 10 minutes after half-time.

Bordeaux are now well-placed for a tilt at the play-offs, with the final to be played at the Stade de France in June.

The away side eased to victory despite seeing Mahamadou Diaby sent off after 29 minutes for a dangerous tackle on Yannick Caballero.

Bordeaux's position in the table marks a swift turnaround since former England World Cup-winner Joe Worsley was promoted to caretaker coach when Rory Teague was fired in mid-November.

But Castres coach Christophe Urios will take over Bordeaux next season.

"We have to be careful not to drown here," said Urios. "We showed zero aggression. I just can't understand it."

"Maybe we'll find a solution under the Christmas tree, a book, rugby for beginners," he said.

Stade Francais returned to winning ways on Saturday with a 19-6 win at struggling Agen, to move up from eighth in the table into the top six, while Toulon secured their biggest win of the season by beating Lyon 40-7 at Stade Mayol.