St Helens booked their place in Super League's play-off semi-finals with a seven-try victory over Castleford.
James Roby scored two first-half tries, both converted by Mark Percival, while Jordan Turner's drop goal put the hosts 13-0 ahead at the break.
The League Leaders' Shield winners ran riot after the break with Turner, Adam Swift, Tommy Makinson, Kyle Amor and Mose Masoe all going over.
Percival kicked four goals to take his tally on the night to 12 points.
Saints will now pick their opponents in a home semi-final but Castleford still have a second chance in next week's preliminary semi-finals.
|Saints going one better|
|St Helens, who are now 80 minutes away from the Grand Final, lost 11-10 to Leeds Rhinos in last season's preliminary semi-finals.|
The game burst into life when Roby scored under the posts from dummy half and the hosts extended their lead to 6-0 with Percival's successful kick.
Roby then grabbed his second try in the space of 10 minutes with a dazzling 25-yard run and Percival was accurate again with the conversion.
St Helens thought they had their third try but Percival's pass to Makinson was judged to have gone forward, but Turner's drop goal right on half-time gave his side into a 13-point lead.
Turner raced in down the middle from 50 yards to give St Helens a perfect start to the second half and Percival added the extras for a third time.
Roby made a last-ditch challenge to deny Castleford's Michael Channing on the line, before Swift's 75-yard try put the game out of reach.
Makinson was able to mark his 100th appearance for St Helens with his 28th try of the season, made by great work from Percival, but his attempt at goal hit the upright.
Amor shrugged off the attention of three Castleford players to score the home side's sixth try and Masoe provided the final try of the night with five minutes remaining.
St Helens assistant coach Keiron Cunningham:
"James Roby has been absolutely outstanding all season but, over the last three weeks, he's been making 65 tackles and 200-odd metres a match and there's not a nine in the world who can even come near that.
"I've done a lot of work with Robes in the last two years, just trying to round off his game.
"There is a lot of stuff he does now which he never used to do. He's definitely in the top three in the world."
Castleford coach Daryl Powell:
"I thought we worked hard in the first half but conceded a couple of soft tries.
"We couldn't get anything from the referee, who I thought was horrendous, although I say that every time I see him referee.
"Saints were just too good for us. We still look like we're low on energy when it gets really tough and in the second half we lost our composure under a fair bit of pressure.
"It was clearly not good enough and we need a response. We've got to be better than that."
St Helens: Wellens; Makinson, Percival, Wheeler, Swift; Hohaia, Flanagan; Amor, Roby, Richards, McCarthy-Scarsbrook, Thompson, Turner.
Replacements: Masoe, Soliola, Manu, Laffranchi.
Castleford: Dorn; Dixon, Webster, Shenton, Carney; Ellis, Finn; Lynch, Milner, Huby, Holmes, Hauraki, Millington.
Replacements: Massey, Clark, Wheeldon, Channing.
Sin Bin: Shenton (63).
Referee: James Child (RFL).