|Coral Challenge Cup quarter-final|
|Warrington Wolves (16) 20|
|Tries: Gelling, Charnley 2, Ashton Goals: Ratchford 2|
|St Helens (8) 18|
|Tries: Lomax, Grace, Naiqama Goals: Coote 3|
Warrington repeated last season's Wembley win over St Helens to reach the semi-finals of the 2020 Challenge Cup.
Jonny Lomax's try helped Saints into an 8-0 lead, but Anthony Gelling, Josh Charnley and Matty Ashton put the Wire eight points in front by half-time.
Regan Grace and Kevin Naiqama scored either side of Charnley's second, but Lachlan Coote missed a difficult kick which would have forced extra time.
Warrington will play Salford in their semi-final on Saturday, 3 October.
- Relive Saturday's Challenge Cup quarter-finals
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- Leeds thrash Hull KR to reach last four
- Salford beat Catalans in extra time
This last-eight tie, which pitted the top two teams in the Super League table against each other, was the most eagerly anticipated of the four quarter-finals and it delivered the closely-fought, high-quality contest many onlookers expected.
After Lomax's early try, Warrington seized control with three scores in quick succession before the interval.
Gelling leapt highest to claim a lofted kick for the Wolves' first and the centre's exceptional offload sent winger Charnley to the line, before Ashton finished off a swift break a few seconds before the half-time hooter.
Back came St Helens as Wales winger Grace dived in at the corner to reduce the gap to two, only for Warrington to cross again in bizarre circumstances when an attempted pass out wide bounced off the head of Gelling into the hands of Charnley, who raced over unchallenged.
Naiqama's close-range effort took the reigning Super League champions back to within two points, but Coote was unable to land the touchline conversion and Warrington held out for the final few minutes to book a semi-final berth.
Warrington head coach Steve Price told BBC One:
"It was a good, hard game with two quality teams going at it. Defensively I thought we were really solid.
"It's the best game Anthony Gelling play since he's been at Warrington and I'm proud because he's worked hard at his game.
"We're still alive in the cup which is pleasing. Every time we play, we go out to be the best version we can be and get wins. We have the opportunity now to go to a semi-final and we'll see how we go."
St Helens captain James Roby:
"It was a really tough game, the scoreline suggests that.
"You can't afford to be off it one bit in these games, Warrington are a quality team.
"Our mindset has to switch to getting to the Grand Final. It's almost tunnel vision. We experienced it last year so we know what it takes to do it."
Warrington: Ashton; Mamo, King, Gelling, Charnley; Austin, Ratchford; Hill, D Clark, Cooper, Currie, Hughes, J Clark.
Interchanges: Murdoch-Masila, Philbin, Davis, Walker.
St Helens: Coote; Welsby, Naiqama, Percival, Grace; Lomax, Fages; Walmsley, Roby, Graham, Taia, Bentley, Knowles.
Interchanges: McCarthy-Scarsbrook, Lees, Amor, Smith.