Brive edged Scarlets 15-11 at Stade Amédée-Domenech on Sunday to ensure the Amlin Challenge Cup semi-finals will be contested exclusively by French clubs.
Brive will now travel Biarritz on Saturday 28 April while Toulon will host Stade Français on Friday 27 April.
Scarlets scored the only try of the game through full-back Liam Williams but it was not enough to topple their hosts, who scored all their points via the boot of inside centre Riaan Swanepoel.
Les Corréziens built their victory on the back of a dominant scrum and a staunch defence.
The scores were locked at 6-6 at half time as Stephen Jones and Swanepoel traded penalties.
Swanepoel put Brive back in front after the break with two more penalties as the Scarlets buckled.
The Scarlets then stunned the home side when Williams plunged over after a slick backline move just before the hour mark to narrow the gap to a single point.
But Swanepoel's fifth three-pointer of the evening two minutes from time ended Welsh hopes in the tournament.
Pens: Swanepoel 5
Try: L Williams
Pens: SM Jones 2
Yellow card: Geraghty (Brive - 52nd min)
Brive: 15 Mathias Atayi, 14 Jacques Boussuge, 13 Ronnie Cooke, 12 Riaan Swanepoel, 11 Sevania Galala, 10 Shane Geraghty, 9 Jean-Baptiste Pejoine, 8 Petrus Hauman, 7 Alexandre Bias, 6 Vincent Forgues, 5 Olivier Caisso, 4 Julien Le Devedec, 3 Pat Barnard, 2 Virgile Lacombe (capt), 1 Jefferson Poirot.
Replacements: 16 Iuri Natriashvili, 17 Davit Khinchagishvili, 18 Alexandre Barozzi, 19 Retief Uys, 20 Poutasi Luafutu, 21 Augustin Figuerola, 22 Scott Spedding, 23 Arnaud Mignardi.
Scarlets: 15 Liam Williams, 14 George North, 13 Gareth Maule, 12 Jonathan Davies, 11 Andrew Fenby, 10 Stephen Jones, 9 Gareth Davies, 8 Ben Morgan, 7 Jon Edwards, 6 Josh Turnbull, 5 Damian Welch, 4 Sione Timani, 3 Peter Edwards, 2 Matthew Rees, 1 Rhodri Jones.
Replacements: 16 Ken Owens, 17 Phil John, 18 Simon Gardiner, 19 Kieran Murphy, 20 Kieran Murphy, 21 Rhodri Williams, 22 Rhys Priestland, 23 Sean Lamont.
Venue: Stadium Municipal
Referee: Wayne Barnes (England)
Assistant referees: Greg Garner (England), Paul Dix (England)