Ian Henderson scored four seconds from time as Catalan resisted a late St Helens comeback to record back to back victories at Langtree Park.
Louis McCarthy-Scarsbrook came close to scoring a minute from time but in a bitter twist of fate, it was Ian Henderson who had the last say.
The opening stages were physical, but despite several opportunities on their opponent’s line, neither side were able to get the scoreboard attendant working.
Catalan tried for the first points on the 20 minute mark after being awarded a penalty for a ball steal, but Thomas Bosc’s shot sailed to the right of the posts.
Bosc’s grubber made the Saints scramble in their in-goal but an honest shake of the head from Catalan captain, Steve Menzies dismissed a potential try when referee, Phil Bentham requested assistance from upstairs.
But the Dragons had by now established a more than fair share of possession and opened the scoring 27 minutes in after a move finished off by Frederic Vaccari, converted by Bosc from the touchline.
Vaccari came close again from another challenging kick stabbed in by Bosc, but Adam Swift palmed the ball safely into the stands.
Catalan were painfully close again from the resultant goal line drop out as exciting French youngster, Morgan Escare raced in under the sticks only to be turned down by Ben Thaler.
Escare wasn’t denied a second time after supporting a Damien Blanch break to score his fourth try in five matches. Again, Bosc kicked the goal to take the half-time score to 0-12.
Saints appeared to have upped the ante after spending a quarter of an hour with coach Nathan Brown, and put themselves back within six points with a seventh minute try.
Sia Soliola burst through the opposition defence, passed inside to Jon Wilkin before taking a return ball to spin over the line in front of the home terrace.
However the Dragons soon brought the margin back to beyond one score through Bosc who avenged his previous miss with two successive successful penalties.
Michael Simon could have lost it for his side when he was sin binned for preventing a quick play the ball when Tommy Makinson broke the line.
Saints used their one man advantage to bring the game back within four points when Alex Walmsley powered over.
Fellow forward, Louis McCarthy –Scarsbrook was tackled just centimetres away from the line but in a bitter twist of fate, Ian Henderson secured the win after former Saint, Leon Pryce collected a misguided pass.
St Helens: Makinson, Swift, Percival, Turner, Meli, Hohaia, Wilkin, Laffranchi, Howarth, McCarthy-Scarsbrook, Soliola, Jones, Wellens.
Replacements: Clough, Greenwood, Walmsley, Tilley
T: Soliola, Walmsley
G: Pervival 2/2
Catalans: Escare, Blanch, Menzies, Millard, Vaccari, Pryce, Bosc, Casty, Henderson, Simon, Taia, Anderson, Baitieri.
Replacements: Mounis, Pelissier, Fakir, Paea.
T: Vaccari, Escare, Henderson
G: Bosc 5/6
Referee: Phil Bentham
Video Referee: Ben Thaler