Top 14 leaders La Rochelle edged closer to a semi-final spot but rivals Clermont faced increasing pressure from Montpellier after losing at home to Brive on Saturday.
La Rochelle's 16-5 home win against Bordeaux extended their lead on second-placed Clermont to 14 points and matched Toulouse's unbeaten record of 11 games from the 2009 and 2012 seasons.
Bordeaux inflicted La Rochelle's last defeat -- a 26-0 rout in November -- but they were unable to reproduce that form Saturday and are now almost certain of missing the top six play-offs in May.
Brock James converted Kini Murimurivalu's 29th-minute try to give La Rochelle a slim 7-5 advantage at the break after Jayden Spence touched down for Bordeaux.
But the hosts pulled ahead after the break after Bordeaux's Hugh Chalmers was sin binned, with James sealing victory with three penalties.
"We got an earful (from manager Patrice Collazo) and that's what we needed after our near catastrophic first half," said La Rochelle's Kevin Gourdon.
La Rochelle have an 18-point advantage on third-placed Montpellier who touched down eight tries to beat Grenoble 54-14 and have a match in hand.
The top two teams qualify automatically for the semi-finals.
But Clermont's shock 26-21 defeat at home to Brive saw their advantage on third-placed Montpellier cut to four points.
Brive achieved just their second away win of the season and move provisionally into sixth -- the last play-off spot -- ahead of Pau who travel to Racing 92 on Sunday.
Montpellier's ninth straight home win gives Jake White's side an eight-point lead on fourth-placed Castres, beaten 17-16 at home by Lyon, and Toulon who play Toulouse in Marseille on Sunday.
Lyon inflicted Castres' first home defeat in eight months and are now two points within sixth spot.
Castres paid for indiscipline with two yellow cards and Rory Kockott missing a chance to seal victory with a late penalty kick.
But Bayonne fell 32-16 at home against Stade Francais leaving them with no chance of playing Top 14 next season.
"We had ambitions to cause everyone problems this season, we couldn't do it," said manager Vincent Etcheto.
"We lacked experience, our squad hadn't enough depth."
Stade Francais, meanwhile, continued their revival with a third win since the now-shelved controversial planned merger with fellow Paris giants Racing.
"We made 11 changes. We took risks," said manager Gonzalo Quesada.
"This allows us to dream now. I hope that if we can have some news quickly on the future of our club that will help us too.
"The players knew how to regroup after the episode of the merger/non merger while it could have blown everything apart."
Their win leaves them three points off the play-off spots but ensured their Basque rivals drop out of the elite after just one season.