Bordeaux-Begles rout Northampton in Champions Cup final rematch
Earlier, Munster's hopes of reaching the last 16 suffered a blow when the two-time champions lost 27-25 in a Pool 2 thriller at Toulon.
English side Harlequins booked their place in the knockout stages with a one-sided 61-10 bonus point win at home to Cape Town Stormers in Pool 3.
Both defending champions Bordeaux-Begles and Northampton were already sure of qualifying before their Pool 4 meeting.
Salesi Rayasi gave the hosts an early lead with an unconverted try. Henry Pollock replied and Frenchman Anthony Belleau converted to give the Saints the lead.
After Northampton's Danilo Fischetti collected a 16th minute yellow card for a scrum offence, fullback Rayasi scored again to restore the Bordeaux-Begles lead.
As Fischetti returned, team-mate Rory Hutchinson replaced him in the sin bin after taking out star winger Louis Bielle-Biarrey.
Again, the hosts exploited their advantage as scrum-half Martin Page-Relo and lock Cameron Woki touched down to put them 24-7 up at half-time.
Rayasi completed his hat-trick two minutes into the second half.
Woki then scored twice either side of a Saints try by Tommy Freeman.
Matthieu Jalibert added an eighth home try before Pollock, booed throughout by the home fans, scored his second.
With the hosts down to 14 after substitute Arthur Retiere staggered off after seeing a yellow card and stars for an illegal tackle on the charging Pollock which left him dazed, Fischetti crashed over to earn Saints a bonus point.
"I'm happy. We won the match we gained a bonus point," said Bordeaux-Begles winger Damian Penaud.
Bordeaux-Begles will visit Bristol in the final round next weekend with first place at stake.
Fine margins
In Toulon, two penalties from Jack Crowley put Munster ahead in a tight first half but Toulon full-back Marius Domon sliced through from close range in the 39th minute, his conversion giving the French side a 7-6 lead at the break.
The first 10 minutes of the second half produced three tries.
With Tadhg Beirne in the sin bin, Toulon struck as Scotland scrum-half Ben White wriggled through to score.
Munster hit back through wing Calvin Nash.
After Toulon wing Gael Drean chipped over the defence, collected on the bounce and skittered through for a try, a penalty from Domon stretched the Toulon lead to 24-13.
Back came the Munstermen with flanker Jack O'Donoghue going over while Toulon's Charles Ollivon was sent to the bin.
The conversion went wide but four minutes later the Irish went in front by a point after a Tom Farrell try was converted by Crowley.
Four minutes from time, Toulon reclaimed the lead as Domon landed his second penalty.
The pool will be decided next week when Munster host Castres and Toulon travel to Gloucester. Bath and Edinburgh look certain to qualify but the other two spots are wide open.
Harlequins made short work of a weakened Stormers at the Stoop to leap-frog the South African franchise into second place in Pool 3 and secured their passage to the last 16.
The London side cut loose in the first half, scoring five tries and chalking up the bonus point as they took a 33-0 half-time lead.
The rout continued in the second half as wing Nick David completed his hat-trick and Quins took their try tally to nine.
Harlequins were coming off three big Prem defeats to Bristol, Sale and Northampton.
"The biggest thing is it was great to see the boys with a smile back on their faces," said coach Jason Gilmore. "It's been tough but we can take lots of confidence from that."