St Helens: (34) 52
Tries: V Anderson, Roby, Cunningham, P Anderson, Pryce, Lyon 2, Gardner, Long
Goals: Lyon 8 Les Catalans: (12) 26
Tries: Rudder 2, Murphy 3
Goals: Frayssinous
Catalans Dragons took the lead after six minutes when Justin Murphy scored the first of his two first-half tries.
But Super League leaders Saints hit back in style with Ade Gardner, Sean Long, Jamie Lyon, Leon Pryce, Keiron Cunningham and James Roby all crossing.
After the break, Sean Rudder grabbed a double for the Dragons while Murphy completed his hat-trick.
But Saints added further tries through Vinnie Anderson, Paul Anderson and Lyon, who also kicked eight goals.
St Helens coach Daniel Anderson:
"We were very good in the first half and were difficult to stop.
"I had a comfortable day as a coach and that is why I was able to rest the likes of Keiron Cunningham, Paul Wellens, Sean Long and Leon Pryce.
"Long got a bit of bump but I don't think there is anything more than that."
St Helens: Wellens, Gardner, Lyon, V. Anderson, Hardman, Pryce, Long, Cayless, Cunningham, P. Anderson, Wilkin, Graham, Hooper. Replacements: Fa'asavalu, Fozzard, Roby, Tyrer.
Catalans Dragons: Frayssinous, Murphy, Wilson, Guigue, Verges, Rudder, Jones, Beattie, Mounis, Guisset, Hindmarsh, Fakir, Cologni. Replacements: Chan, Berthezene, Fellous, Jampy.
Referee: K Kirkpatrick (Warrington).