Leinster will face Bordeaux-Begles in this year's Investec Champions Cup final in Bilbao after the reigning champions beat Bath 38-26 at the Stade Atlantique Bordeaux Metropole.
The English champions were chasing Bordeaux from the moment they leaked an early try, with their opponents showing a ruthless streak when converting their chances.
Bordeaux were worthy winners and they advance the final in Bilbao on May 23 when they will look to retain their title against Leo Cullen's side, who held off Toulon in Saturday's semi-final.
Kick-off was delayed by 10 minutes to allow fans to get into the stadium and Bath appeared to be caught cold when their line was breached after just 110 seconds, their lack of outside defence exploited through Damian Penaud before Marko Gazzotti arrived to crash over.
England scrum-half Ben Spencer was at the heart of the response as he delivered kicks to each wing, the second picking out Will Muir who was presented with a simple run in.
Bath were exposed out wide again as Louis Bielle-Biarrey struck in the left corner but it was a line-out drive a phase earlier that had really softened up the defence.
Alfie Barbeary was prominent as Bath pounded the home whitewash but when they scored their second try it was through the handling of their backs and a clever run by Henry Arundell followed by a superb diving finish by Muir.
There was no sign of the breathless pace letting up as lethal Bordeaux struck again with Maxime Lucu the scorer after the ball had been kept alive brilliantly as Bath ran out of defenders.
The final act of the first half was Lucu landing a penalty to establish a 24-12 lead and Bath were in danger of being cut adrift.
It was crucial they scored next and only an inaccurate pass from Finn Russell to Santiago Carreras prevented them crossing in the right corner.
Bordeaux's defence continued to scramble desperately and it finally cracked in the 51st minute when Louie Hennessey side-stepped over, ignoring the overlap outside him.
Matthieu Jalibert was becoming increasingly influential with Bielle-Biarrey also looking to seize the moment as the favourites cut loose with increasing frequency.
Bath were hustling to good effect, however, and trailed by just five points with 15 minutes to go, even if they were under continued pressure.
A powerful Bordeaux line-out drive appeared to have finished in a try but the ball slipped out of the hands of Gaetan Barlot as he went over.
Charlie Ewels was shown a yellow card for pulling down the maul and Bath finally cracked when giant prop Ben Tameifuna surged over in the 69th minute before Temo Matiu and Tom Carr-Smith exchanged late tries.
