The 34-year-old lock Adam Coleman and 29-year-old flanker Lachlan Swinton were in the engine room of a dominant performance from the French 14 outfit on Saturday as they ran out convincing 41-19 winners at the San Mames Stadium in Bilbao.
Coleman, a 38-time capped Australia lock between 2016 and 2019 before he later began representing Tonga on ancestry grounds, played the first half, excelled in the opening half, helping crush the Irish into near-submission at 35-7 up at the break.
When the former Western Force and Melbourne Rebels second-rower came off after the break, he was replaced by Sydney flanker Swinton, who played the last of his seven Wallabies Tests against Wales in 2021.
Leinster had no answer to the inspired French outfit, their hopes of a fifth Champions Cup title shattered in that shocking first half which was illuminated by two dazzling tries from the current biggest star in world rugby, French wing wizard Louis Bielle-Biarrey.
Captain and scrumhalf Maxime Lucu, player of the match in both the semi-final and final, was scarcely any less brilliant, also going over as Bordeaux, winners against Northampton in the final last year, ran in five first-half tries, with Pablo Uberti and Yoram Moefana on the scoresheet too.
Tommy O'Brien, Joe McCarthy and Garry Ringrose touched down for Leinster but they were never in the hunt, as Lucu kicked a couple of second-half penalties to finish with a personal haul of 21 points on a scorching day to seal a comprehensive victory.
It was a case of dispiriting deja vu for underdogs Leinster, who since winning their fourth European title in 2018, have fallen in four finals against French sides.
Last year, another Wallaby Pete Samu played alongside Coleman as Bordeaux triumphed, but he's since left for the Waratahs, while Swinton has come to the fore.
Bordeaux assistant coach Noel McNamara told the BBC: "We spoke about (Masters golf champion) Rory McIlroy in the lead-up to the quarter-final against Toulouse. Good players win one green jacket - great players win two.
"We have fantastic players. They made the decision that one Champions Cup is not enough."