It came at a cost, though, with Leon Pryce limping out after only five minutes, although coach Royce Simmons would have been pleased to see Bath-bound Kyle Eastmond kick three goals as his side won the try count 4-3.
Catalan began the brighter but it was Saints who scored first when Flannery crossed following good work by Eastmond, Michael Shenton and the supporting Gardner.
Eastmond was again involved in Gardner's try, offloading to Paul Wellens, who in turn sent the winger over.
Dragons replied when Sa followed up a high kick from Dureau, which Gardner fumbled, to touch down.
But the home side looked out of it when Graham went over under the posts and Moore put the gloss on a five-man move started by Lee Gaskill's break either side of the interval.
Saints thought they had scored again through Andrew Dixon, only to have that effort ruled out by the video referee and from the resulting penalty Catalan went up the other end and scored when Damien Blanch knocked back another Dureau kick to Menzies.
The home side continued to press and were rewarded in the 78th minute when Dureau scored under the posts to set up a grandstand finish.
And although the Dragons sought another late score, Saints managed to keep them at bay.
Bookmark with:
What are these?