|Betfred Super League play-off semi-final|
|St Helens (26) 40|
|Tries: Fages, Naiqama, Thompson, Lomax, Taia, Percival 2 Goals: Coote 6|
|Wigan Warriors (6) 10|
|Tries: Marshall, French Goal: Hardaker|
St Helens reached their first Super League Grand Final since 2014 by thrashing reigning champions Wigan.
Saints were irresistible in the first half and led 26-6 with tries from Theo Fages, Kevin Naiqama, Luke Thompson and Jonny Lomax.
Zeb Taia's score and a Mark Percival double extended the lead to send Saints to Old Trafford on 12 October.
Wigan will get another chance to reach the Grand Final when they host Salford in the second semi-final on 4 October.
- Relive how St Helens reached the Super League Grand Final
- Salford beat Castleford to reach semi-final
- Super League: How do the play-offs work?
Runaway League Leaders' Shield winners Saints finished the regular season 16 points ahead of the second-placed Warriors and won all three of the previous meetings between the sides this term.
And although Wigan welcomed back prop Oliver Partington from a one-game ban and vastly experienced back-row Sean O'Loughlin for his 450th appearance for the club, they proved no match for rampant Saints.
Justin Holbrook's side, beaten by Warrington in the semi-finals 12 months ago, played with tempo and raced into a 12-0 lead within 10 minutes.
Fages touched down after latching on to Lachlan Coote's reverse grubber kick before Naiqama intercepted George Williams' pass inside own half to race away and score.
Coote extended the lead with a penalty before Wigan scored against the run of play when Liam Marshall raced clear to go over from Chris Hankinson's pass.
But Saints added two more tries before the break as first Thompson and then Lomax charged over from close range.
Wigan needed to score first after half-time to stand any chance and those hopes were soon extinguished when Coote put Taia over from close range.
Percival added the gloss to an impressive Saints display when he first took Lomax's looped pass to dive over in the corner and then stepped past a covering defender to add his second.
Bevan French went over for Wigan late on but that was scant consolation as Saints celebrated on the final hooter.
Justin Holbrook told BBC Radio 5 Live Sports Extra:
"We played brilliantly in that first half and we've come away with a good win in the end.
"I do know the two weeks we've had preparing for this is as good as I've ever had. The boys and I were clear about what we needed to do tonight.
"It's one thing saying it, you've got to be able to do it and we've done that tonight - but we've got to do it again."
Wigan coach Adrian Lam told BBC Radio 5 Live Sports Extra:
"We knew we had to come here and start really well and stay in the game as long as possible before we turned it up a bit.
"We missed a jump at the start, Saints came out at 100mph, which we anticipated, but they were too fast, too strong and defended tougher.
"We got zapped of energy early on and they rolled through the middle of us. If it was going to happen then rather this week than in two weeks.
"We have to pick ourselves up, focus on next week against Salford and get the job done."
St Helens: Coote, Makinson, Naiqama, Percival, Grace, Lomax, Fages, Walmsley, Roby, Thompson, Taia, Peyroux, Knowles.
Interchanges: McCarthy-Scarsbrook, Amor, Ashworth, Smith
Wigan Warriors: Hardaker, Marshall, Hankinson, Gildart, Burgess, Williams, Leuluai, Clubb, Powell, Partington, Isa, Farrell, O'Loughlin.
Interchanges: Byrne, Flower, French, Smithies.
Ref: Chris Kendall (RFL).