St Helens kicked off the Super 8s by sending Castleford to their first home defeat of the season.
Outside the top four at the end of the regular season, Saints built on an encouraging recent run of three wins with a 26-12 win that sends a message that they mean business in the run in.
Runaway league leaders Castleford weren’t at their best, and must now wait to confirm a home semi final.
But take nothing away from Saints who backed up a stern defensive effort with creativity when it mattered, despite surrendering plenty of ball to the hosts.
Their rearguard action was built in the first half, where they managed to keep the Tigers scoreless.
Zeb Taia’s solitary try was improved on by Mark Percival, who also added a penalty to give Saints an 8-0 half time lead.
A Jonny Lomax mistake, kicking off on the full at the second half, threatened to undo their hard work, but some excellent line defence kept the Tigers at bay, for eight minutes at least.
After a couple of repeat sets, it was a soft score for Saints to concede, Adam Milner going over from dummy half to help reduce arrears to 8-6.
Every Super League side this season has succumbed to Castleford’s relentless repeat scoring, but Saints had different ideas and within five minutes they had restored their two score advantage.
Luke Thompson broke down the left, and quick hands between Morgan Knowles and Theo Fages following the play the ball saw James Roby crash over.
Minutes later they could have stretched their lead when a clever set play right saw Lomax fling out a quick pass to Tommy Makinson, who was just behind play and the ball found touch.
That could have proved costly straight away, when Jy Hitchcox had a run to the corner, only to be denied by a superb try saving tackle by the lively Lomax.
The next try was going to be crucial, and it went to Saints 12 minutes from time – a smart kick from Matty Smith was pounced upon by Lomax, who was well worth the try.
A 14 point deficit going in to the final 10 minutes would prove too tough an ask, even for Castleford.
They briefly threatened a comeback, Joel Monaghan’s converted score bringing them back within eight points, but Saints made sure with five to go when Roby just made it over the line under the attention of two defenders.
The win lifts Justin Holbrook’s men in to the top four, albeit perhaps temporarily with rivals Hull, Salford, Wigan and Wakefield all in action on Friday night.