Warrington 30 (16)
Tries: Wood, Barnett, Westwood, Kohe-Love, Martin Gleeson, Bridge
Goals: Briers 3
St Helens 38 (28)
Tries: Wilkin, Gardner 2, Wellens 2, Talau, V Anderson
Goals: Lyon 5
St Helens produced a breathtaking 21-minute first-half master class to secure a thrilling win.
Wolves stormed into a 16-0 lead through tries from Paul Wood, Richie Barnett and Ben Westwood.
But Saints hit back with tries from Jon Wilkin and a brace apiece from Ade Gardner and Paul Wellens to lead 28-16 at the break.
St Helens added further tries from Willie Talau and Vinnie Anderson to wrap up victory.
Warrington coach Paul Cullen, looking ahead to the play-offs:
"There were great signs of the character that we need to take us to the next level.
"We're hardened by the season we've had and our win against Hull last week.
"We've attempted to take on the most offensive side in the competition and run them off the park - and we very nearly did it."
St Helens coach Daniel Anderson:
"We weren't at our best and we weren't at our worst.
"Our energy levels were down and there's been a lot of flu in the camp, which I've been affected by myself.
"But to score 38 points is an achievement. We showed Warrington are a very good side with the ball in hand because they can tear you apart."
Warrington: Riley, Fa'afili, M. Gleeson, Kohe-Love, Barnett, Bridge, Briers, Wood, Sullivan, Rauhihi, Swann, Wainwright, Westwood.
Replacements: Penny, M Gleeson, Parker, Cooper.
St Helens: Wellens, Gardner, Lyon, Talau, Meli, Pryce, Long, Cayless, Cunningham, P Anderson, Gilmour, Wilkin, Bennett.
Replacements: Roby, V Anderson, Graham, Fa'asavalu.
Referee: A Klein (London)