That 28-21 triumph over the French giants in Marseilles secured a fourth Heineken Cup berth for Welsh sides, with the Scarlets the team to benefit.
The Scarlets missed out on automatic qualification by finishing as the fourth Welsh region in this season's Magners League and had been preparing for a year in the Amlin Challenge Cup.
But Sunday's historic result now means the Llanelli-based outfit will have the chance to go one better than their 2002 and 2007 Heineken Cup semi-final defeats to Leicester when the competition kicks off again in October.
And Scarlets team manager Garan Evans has no doubt that the news is a massive boost to the region in more ways than one.
"It's so important to us as a region," said Evans.
"You can look at every aspect - there will be more season ticket holders and it helps if you are looking to bring players in. It's easier to sell the club when it's in the Heineken Cup.
"We got in through the back door when we would have liked to have done it ourselves. But all credit to the Blues for helping out the Scarlets."
And while Blues boss Dai Young was enjoying his side's moment of glory at the Stade Veledrome, he too expressed his delight at the Scarlets' presence in next year's top-tier tournament.
"I'm sure we've put a lot of smiles on a lot of Scarlets' fans' faces and I'm thrilled for that as well," said Young.
"They deserve to be in Europe - a lot of good things are happening down there so it will be great to have four Welsh regions in Europe next year."