The Blues made it three successive years of continental success for the Magners League with a stunning win over Toulon in front of a close to 50,000-strong crowd at the Stade Veledrome in Marseilles.
Dai Young's men followed 2008 Heineken Cup winners Munster and 2009 champions Leinster in picking up a European trophy as they claimed the Amlin Challenge Cup despite facing French opposition on French soil.
The Blues are the first Magners League side to win Europe's second-tier competition and the first Welsh team ever to claim a continental crown.
Having narrowly missed out on a Magners League Play-Off spot with a fifth-place finish, the Blues produced a scintillating second-half performance to triumph 28-21 in a thrilling Challenge Cup Final.
Tries from Jamie Roberts, Bradley Davies and Leigh Halfpenny saw the Welsh capital outfit record a truly memorable victory in front of a partisan crowd in what was effectively a home fixture for big-spending Toulon.
The Blues trailed 13-6 at half-time, with Toulon looking in control in the final game of the European club season.
But the Blues never gave up despite being written off by commentators and critics alike and it was they who were celebrating when the final whistle blew on a thrilling encounter.
As well as going someway to making up for the Blues' heartbreaking Heineken Cup semi-final defeat to Leicester Tigers this time last year, the win ends a 15-year drought for Welsh sides in continental competition.
Cardiff, Pontypridd and Caerphilly had all gone close in previous years, but it is the Blues who will be forever remembered as Welsh rugby's European pioneers.
The result also brought a second piece of good news to Magners League rugby, with the Scarlets benefiting from the Blues' breathtaking display.
Nigel Davies' men had missed out on Heineken Cup qualification through the Magners League but will now be back at Europe's top table next season after the Blues secured an extra Welsh place in the competition.
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