Investec Champions Cup
Exeter (5) 17
Tries: Brown-Bampoe (2), Hammersley Cons: Slade
Bordeaux (31) 69
Tries: Lucu (2), Penaud (3), Bielle-Biarrey (2), Lamothe, Cazeaux, Jalibert, Lesgourgues Cons: Jalibert 6, Cazeaux
Damian Penaud scored a hat-trick as Bordeaux-Begles hammered Exeter Chiefs to all but end the hosts' chances of qualifying for the last 16 of the Investec Champions Cup.
Exeter wing Paul Brown-Bampoe ran in a sensational length-of-the-field try on his first Champions Cup appearance to open the scoring.
Bordeaux quickly responded through tries from France duo Maxime Lucu and Damian Penaud, and continued to be at their clinical best in a dominant first half.
Penaud's mazy run set up Lucu for a second, with replacement Louis Bielle-Biarrey and hooker Maxime Lamothe also scoring in a rampant opening period.
Both Penaud and Bielle-Biarrey grabbed their second tries in the second half, with Cyril Cazeaux also crossing.
Brown-Bampoe did grab a second score for the Chiefs early in the second period, but Exeter remained second best throughout the game.
Penaud looked set to complete his hat-trick but unselfishly passed the ball to Matthieu Jalibert for another try, while replacement Yann Lesgourgues also helped himself to a score.
A red card for a high tackle by Toma Taufa and a sharp finish from Ben Hammersley gave Rob Baxter's side hope of a losing bonus point in the closing stages.
However, Penaud instead completed his hat-trick and Bordeaux remained resolute in defence to deny the hosts a fourth try and bonus point.
The top four qualify for the last 16, with the top two in each of the four pools having home advantage for the knockout stage.
Defeat drops the Chiefs to sixth in pool one, meaning they will need to rely on other results and secure a big bonus-point victory in their final game against Ulster on Friday.
It also marked the most points they have conceded at home since gaining top-flight status in 2010, and their 12th loss from 13 games this season.
On paper, the fixture was heavily weighted towards the French visitors at Sandy Park.
The Chiefs have won only once all season, compared with a side who scored 82 points across their opening two pool games against Leicester Tigers and Ulster, and are top of the Top 14.
Bordeaux spent the early exchanges camped inside the Exeter 22 until Brown-Bampoe intercepted the ball, fended off two defenders and ran the length of the field to score an unexpected opening try.
However, the Top 14 side, who came into the fixture on a seven-match winning run, instantly responded when Yoram Moefana sliced through some weak defending to send Lucu in untouched.
France wing Penaud was the beneficiary of more sharp attacking play from Lucu as he cantered in for the visitors' second try.
One of the tournament favourites did not let up, Penaud turning provider for Lucu with a mazy run to set up the scrum-half as the Top 14 side took control.
A first-half injury to full-back Romain Buros prompted the introduction of 21-year-old Bielle-Biarrey, who wasted no time in getting on the scoresheet with a sharp finish, before hooker Lamothe dotted down from the back of a maul in the final play of the first half.
Despite the victory being all but sealed by half-time, Bordeaux continued to be ruthless in the second period to increase their points difference as they aim to secure top seeding.
Toulouse's failure to pick up a bonus-point victory in South Africa over the Sharks means it puts the Top 14 leaders in pole position to claim that spot in pool one.
Bordeaux finish the pool phase with a home game against the Sharks next Sunday (13:00 GMT).
Exeter: Wyatt; Hammersley, Wimbush, Tua, Brown-Bampoe; Slade, Townsend, Sio, Frost, Iosefa-Scott, Jenkins (capt), Molina, E Roots, Vermeulen, Fisilau.
Replacements: Norey, Goodrick-Clarke, J Roots, Tuima, Tshiunza, Cairns, Haydon-Wood, Rigg.
Red card: Toma Taufa (69 mins)
Bordeaux: Buros; Penaud, Moefana, Van Rensburg, Uberti; Jalibert, Lucu (capt); Boniface, Lamothe, Sadie, Petti, Cazeaux, Swinton, Matiu, Tatafu.
Replacements: Latterrade, Poirot, Taufa, Ricard, Gazzotti, Vergnes-Taillefer, Bielle-Biarrey, Lesgourgues.
Referee: Ben Whitehouse (Wal)