Betfred Super League
Warrington (0) 6
Tries: Clark Goals: Ratchford
St Helens (12) 18
Tries: Sironen, Percival, Mbye Goals: Percival (3)
St Helens held off a fierce Warrington fightback to make it eight wins on the bounce and stay in the fight for the League Leaders Shield.
The reigning champions led through tries from Curtis Sironen and Mark Percival in the first half and seemed to be cruising to a comfortable win.
Wire, however, needing a result to be sure of a top-six place going into next week's final round of league fixtures, came up with a spirited reply.
Daryl Clark's try had the home fans at the Halliwell Jones Stadium dreaming of an end to a five-match losing streak against their local rivals.
Saints held firm, despite losing Jon Bennison to the sin-bin in the closing stages, with Moses Mbye providing a killer try in the final minute.
The stakes were high for both teams going into this derby, with Saints tied in a three-way scrap for top spot with Wigan and Catalan Dragons, and Wire knowing anything but a win could see them lose their play-off spot to Salford.
Saints roared out of the blocks and Wolves struggled to cope with their hard running and slick passing, and the visitors were two converted tries ahead within 20 minutes.
Jonny Lomax was the architect of the first score, his short pass sending forward Curtis Sironen, back after five matches out through injury, crashing over. Percival added the extras.
Percival added a try of his own after another swift, slick attacking move from Paul Wellens' side, Lomax again at the crux of the move and Jack Welsby racing into the line to deliver the perfect pass for the centre to burst over the line.
Warrington roused themselves and fought hard to gain a toehold against a stern defensive effort from Saints.
Two brilliant try-saving tackles by full-back Welsby, outstanding throughout, kept Warrington at arm's length as right-wing Matty Russell was denied on one side and then left-wing Matty Ashton on the other, either side of half-time.
Warrington refused to be cowed, and they got the try their efforts deserved when Clark, playing against the club he will join next season, crashed through two tacklers to go over.
Stefan Ratchford's conversion put Wire within a score but Jon Bennison's pull-back on Matty Nicholson, as the home side threatened to break away, thwarted their best scoring chance.
Bennison was given 10 minutes in the sin-bin for that offence but it proved crucial.
Saints wrapped up the win as the clock ticked down, Moses Mbye spotting a gap in the exhausted defence to dart over from acting half-back.
Warrington: Dufty; Russell, Wrench, Ratchford, Ashton; Hayes, Drinkwater; Mikaele, Clark, Vaughan, Currie, Nicholson, Crowther.
Interchanges: Harrison, Kasiano, Philbin, Walker (Minikin).
St Helens: Welsby; Makinson, Percival, Davies, Bennison; Lomax, Dodd; Lees, Roby, Mata'utia, Sironen, Batchelor, Knowles
Interchanges: McCarthy-Scarsbrook, Bell, Royle, Mbye. (Baxter).
Referee: Jack Smith.