Warrington came away from their first visit to Saints' new stadium at Langtree Park having put five points between the two clubs bidding to be Super League runners-up going into the play-offs.
A game of play-off intensity was largely controlled by the Wolves' old heads, Lee Briers and Brett Hodgson. Warrington, who play Leeds at Wembley in less than three weeks, also benefited from some strong displays by forwards putting down a marker for a place in the Cup final side.
Even if they concede reluctantly that no one is likely to catch Wigan and deny them the League Leaders Trophy, these neighbours went into this final Monday night match of the season with second place to play for.
It was Warrington who showed the early urgency, with an opening try to Brett Hodgson, sliding over when the Saints defence stood off him. Still inside the first 10 minutes, Lee Briers hoisted a high bomb, Joel Monaghan won the jump against Francis Meli and Chris Hill was on hand to score.
Hodgson's conversion made it double figures, with Saints' efforts to get into the game suffocated by remorseless defence. On attack, the Wolves created a carbon-copy move, Briers kicking, Monaghan touching down, but the video referee ruling out the try on the grounds that Meli had already defused the kick.
Meli's break then produced the first chance for the slow-starting Saints, but Jonny Lomax knocked on. The home side were stirring themselves, however, Hill's loose pass surrendering possession and Paul Wellens putting Josh Jones over. Warrington were harming their cause by conceding a string of penalties.
But the Wolves started the second half as powerfully as they had the first, however, with Briers jinking and teasing and Hodgson supplying the perfect short pass to send Trent Waterhouse charging in. Chris Riley had two tries disallowed, one for treading in touch and one for Ryan Atkins' forward pass, as the Wolves threatened to kill off the opposition.
Saints were hanging on with determination, with Michael Monaghan the next to go close to a potentially decisive try. It finally arrived just after the hour, Riley at last getting his reward when he picked up Atkins' pass off his bootlaces to go over in the corner.
There was little doubt after that Saints were going to lose to a side other than Wigan for the first time under the Mike Rush-Keiron Cunningham coaching partnership, even though Paul Wellens got one back six minutes from time to jangle a few nerves.
St Helens Wellens; Makinson, Shenton, Jones, Meli; Hohaia, Lomax; Perry, Roby, Laffranchi, Puletua, Flannery, Wilkin. Substitutes used McCarthy-Scarsbook, Clough, Flanagan, Dixon.
Warrington Hodgson; J.Monaghan, Ratchford, Atkins, Riley; Briers, Myler; Morley, Higham, Hill, Waterhouse, Westwood, McCarthy. Substitutes used Wood, M.Monaghan, Grix, Cooper.
Referee R.Silverwood (Mirfield)