Catalans (22) 28
Tries: Bell (2), Bosc (2), Mogg Goals: Bosc (4)
St Helens (10) 32
Tries: Gardner (2), Wellens, Meli, Pryce, Wheeler Goals: Long (3)
Ade Gardner's two tries helped St Helens claim victory
Gary Wheeler's late try sealed victory as St Helens came from behind to win and return to the top of the table.
A brace of tries each for Stephen Bell and Thomas Bosc put the Dragons on top at half-time but Ade Gardner's try just after the restart inspired the revival.
Leon Pryce, Paul Wellens and Francis Meli also scored as Saints looked to be on course for victory, before Adam Mogg scored for the Dragons late on.
But with two minutes left Wheeler's try, converted by Sean Long, won it.
The Saints had trailed 22-10 at the break but showed great resolve to battle back and ran in three tries in 15 minutes without reply before surviving the Catalans late revival.
Defeat consigned Catalans to their fifth straight defeat.
Catalans Dragons: Greenshields, Duport, Bell, Baile, Pelo, Mogg, Bosc, Carlaw, McGuire, Guisset, Fakir, Touxagas, Bird. Replacements: Ferriol, Mounis, Bentley, Casty.
St Helens: Wellens, Gardner, Gidley, Wheeler, Meli, Pryce, Long, Graham, Cunningham, Hargreaves, Gilmour, Flannery, Puletua. Replacements: Roby, Clough, Fa'asavalu, Ashurst.
Referee: P Bentham (Warrington)