Gareth Anscombe showed nerves of steel to secure Cardiff Blues' second European Challenge Cup title in an unforgettable 31-30 comeback win over Gloucester at Bilbao's San Mames Stadium.
Anscombe missed a chance to draw Cardiff level at 30-30, failing to convert Blaine Scully's 75th-minute try, but he was back on target two minutes from time with a match-winning penalty from the left wing.
The Blues were teetering on the brink when trailing 20-6 at half-time, with Henry Trinder and Mark Atkinson crossing for Gloucester and the Welsh region losing Josh Navidi and Owen Lane to injury.
However, the 2010 champions stormed back with tries from Tomos Williams and Garyn Smith in a rousing 13-point surge, including Jarrod Evans' third successful penalty.
James Hanson's maul try and Billy Twelvetrees' continued accuracy off the tee - he finished with 15 points - gave Gloucester a 30-23 lead, but it was not enough as Lewis Ludlow's yellow card was followed by Scully's try and full-back Anscombe's all-important kick.
It was final heartbreak again for the Cherry and Whites, who lost the 2017 decider to Stade Francais.
Cardiff's stirring display topped off a memorable few days for sport in the Welsh capital, following Cardiff City's promotion back to the Premier League.
It provided the ideal send-off for departing head coach Danny Wilson, backs and attack coach Matt Sherratt and retiring prop Taufa'ao Filise.
Already missing Sam Warburton, club captain Gethin Jenkins and Alex Cuthbert, Cardiff lost Navidi to a shoulder injury after he had set up Evans' lead penalty in the opening minutes.
In response, Gloucester winger Trinder scored from Billy Burns' pinpoint crossfield kick for the first of the night's six tries. Twelvetrees drew the tricky conversion in for a 7-3 lead.
Following Callum Braley's terrific try-saving tackle on Scully, Cardiff forced a second kickable penalty which 21-year-old fly-half Evans slotted over, 15 minutes in.
Twelvetrees restored the four-point gap after Seb Davies failed to roll away, and Gloucester's grizzled prop Josh Hohneck was denied a magical try assist when his one-handed offload to Ludlow was ruled forward.
However, Johann Ackermann's powerful side put together a stunning 10-point salvo just before the break.
Twelvetrees, Trinder and Braley crafted a slick try from deep which centre Atkinson finished off behind the posts. Twelvetrees converted and also tagged on a penalty with the final kick of the first half.
The second period was only 50 seconds old when Cardiff scrum-half Williams dribbled through from an Anscombe kick and beat Braley to touch down. Evans converted and then punished Jack Polledri for going off his feet.
The young Blues stand-off increased his influence by threading a kick through for replacement winger Smith to dot down in the 54th minute.
Evans curled over the conversion too, but a costly knock-on from his half-back partner Williams indirectly led to Hanson piling over from a well-executed drive.
Twelvetrees kept up his 100 per cent record with the conversion and a 62nd-minute scrum penalty.
However, Cardiff had more in reserve, benefiting from Gloucester flanker Ludlow's sin-binning for infringing at a maul.
Cardiff put width on the ball and sent Scully over in the right corner, the American producing a textbook finish despite Twelvetrees' despairing tackle.
Although the touchline conversion was pulled wide, Smith's chasing down of Tom Marshall saw the Gloucester winger pinged for not releasing and Anscombe emerged as Cardiff's late hero.