Biarritz scored three first-half tries while Gloucester had a player in the sin-bin - prop Dario Chistolini and then hooker Koree Britton - and there was no way back from a 13-point interval deficit.
France Under-20 wing Teddy Thomas scored two tries on his European debut for the visitors while hooker Arnaud Heguy also touched down, with centre Damien Traille dropping a goal and scrum-half Dimitri Yachvili converting all three touchdowns and booting a penalty for a 27-14 interval advantage.
And with Biarritz's American international wing Takudzwa Ngwenya causing mayhem in broken play, his enterprise delivered a fourth Biarritz try after 57 minutes for centre Benoit Baby that saw Yachvili add the extras, before he converted substitute Seremaia Burotu's late score.
Gloucester had to content themselves with four Freddie Burns penalties, tries from Mike Tindall, Shane Monahan and Huia Edmonds, plus two Burns conversions, but they were outclassed by a Biarritz team that will now be away to Wasps or Leinster in the semi-finals later this month.
And confirmation of Biarritz's dominance arrived through their points total being the most Gloucester have conceded - home or away - this season.
Gloucester showed five changes from the side that beat reigning Aviva Premiership champions Harlequins last Friday, which included a return for centre Tindall and lock Will James replacing an injured Jim Hamilton, while Chistolini was a late call-up for Shaun Knight.
Biarritz, meanwhile, were without their former Gloucester and England wing Iain Balshaw through injury in a team captained by ex-France international back-row star Imanol Harinordoquy.
Former Gloucester favourite Yachvili missed an early penalty for Biarritz, but Traille dropped a goal after Burns booted Gloucester ahead during a lively opening quarter.
Gloucester enjoyed early territorial supremacy and that pressure was rewarded when Burns floated an exquisite pass to Tindall, who had the simple job of finishing off.
Burns' approach work would have impressed watching British and Irish Lions head coach Warren Gatland and England boss Stuart Lancaster, yet Biarritz stole the initiative after 26 minutes following a Yachvili penalty.
Chistolini had been sin-binned for tackling without the ball before a poor kick by Burns was gathered by Ngwenya, who powered through two weak tackles and sent Thomas sprinting across.
Yachvili added the extras and although Burns kicked another penalty, Gloucester again pressed the self-destruct button when hooker Britton was yellow-carded for tackling Yachvili in mid-air.
And Biarritz punished them once more, this time through a superbly-placed Yachvili kick that Thomas caught to claim his second touchdown, with the scrum-half converting.
Referee John Lacey then departed through injury, accompanied by ironic cheers from the Gloucester faithful, and Burns completed his penalty hat-trick after assistant Dudley Phillips took over the senior officiating role.
But Biarritz were in no mood to take a collective foot off the pedal and more superb work by their forwards resulted in a try for Heguy from a driven lineout that Yachvili converted.
It underpinned a 27-14 half-time lead for Biarritz, with the visitors having scored 24 of their points while Gloucester were a man down.
And there was no reprieve for Gloucester in the third quarter despite a Burns penalty, as Ngwenya sprinted away from inside his own 22 and fed Baby with a scoring pass that left the home side reeling.
Gloucester tried to recover during the closing quarter but Biarritz had already inflicted irreparable damage as they marched on in defence of a trophy they secured with victory over Jonny Wilkinson's Toulon last season.
And they struck again when Burotu touched down five minutes from time, with Yachvili's conversion taking Biarritz past 40 points and rendering a late yellow card for Harinordoquy - and consolation touchdowns for Monahan and Edmonds - irrelevant.
- Sports & Recreation
- Dimitri Yachvili