Thomas Bosc's last-minute drop-goal decided a captivating Challenge Cup-tie after Crusaders had staged a breathtaking fight-back.
The Welsh side trailed by 24 points shortly before half-time, but got on level terms in the last ten minutes before Bosc struck to take the 2007 Wembley finalists into this year's quarter-finals.
It was a cruel way to go out, but ultimately Crusaders paid for their defensive frailties in the first 40.
Unsurprisingly, after his livewire debut in Edinburgh, Crusaders gave a first start at scrum-half to Jarrod Sammut, and it was his flash of improvised brilliance that produced the game's first try – an outrageous back-handed pass to release Clinton Schifcofske to score for the club for the first time. Michael Witt converted from the touchline and it already looked ominous for the Catalans.
Instead, that turned out merely to be a prelude to a passage of play that they dominated completely. Within five minutes, the Dragons were level when Casey McGuire exploited poor blindside defence to give Setaimata Sa his first.
McGuire and Dimitri Pelo then breached the Crusaders with equal ease for Steven Bell to score and Olivier Elima's pass sent Bosc over the try-line untouched.
The home side were struggling to hold the strapping Sa, who claimed his second from Bosc's cross-field kick.
By the time Dane Carlaw went over, immediately after his introduction from the bench, Crusaders' defence was a disgrace. Their punishment was compounded by Bosc, kicking despite a painful foot, landing all five conversions. They desperately needed some encouragement before half-time and got it when Gareth Thomas showed considerable dexterity to take the ball and pass it on rapidly enough for Vince Mellars to score.
Rhys Hanbury also had one disallowed just before the break as Crusaders hinted at a recovery.
Even without the injured Witt for most of the second half, Crusaders almost turned that hint into a reality.
Frank Winterstein started their revival by stretching over the line, although it was interrupted by Sa completing his hat-trick.
Peter Lupton got over for Crusaders, followed by a sparking little kick and chase try from Sammut, who was also involved with Jason Chan in setting up the try from Nick Youngquest that tied the scores.
Schifcofske, kicking in place of Witt, could not land the conversion from the touchline and, amid mounting tension even in a sparse crowd at the Racecourse Ground, Sammut missed with his drop-goal attempt.
So did Bosc with his first effort, but the Frenchman held his nerve to win a match that was a classic of its type.
Crusaders: Schifcofske; Thomas, Mellars, Hanbury, Youngquest; Witt, Sammut; O'Hara, Withers, Bryant, Hauraki, Chan, Trimarchi. Substitutes used: Thackray, Lupton, Flower, Winterstein.
Catalans: Pelo; Bell, Raguin, Sa, Vaccari; McGuire, Bosc; Ferriol, Baile, Guisset, Elima, Mounis, Johnson. Substitutes used: Carlaw, Bentley, Fakir, Casty.
Referee: I Smith (Oldham)