Paul Wellens’ side registered seven tries with the likes of Tristan Sailor, Mark Percival and Curtis Sironen running a lacklustre Castleford ragged.
After the game, Wellens said: “Our effort areas and approach to games has been good for a number of weeks and it was there again tonight,” said the Saints boss.
“If I am being hypercritical, we left a few points out there, but it is the sign of a tough team when you can win games like that. The 40 points is excellent but the zero means a lot more to me.
“You don’t go into big games thinking about scoring 40 points. but your defensive resilience and application is quite often what sees you home in those matches.”