Daryl Powell’s side produced a remarkable display last night to take their first step towards a potential Grand Final appearance, fighting against the odds to stun Warrington Wolves in this sudden-death play-off eliminator.
Despite missing eight first-team regulars, fifth-placed Castleford - with Jordan Rankin and Liam Watts in immense form - managed to scrap and edge their way to a dramatic success.
It was not without tension; Chris Clarkson - one of their unsung heroes - made a vital try-saving tackle on Jake Mamo with only seconds remaining just as the Warrington replacement looked set to break Castleford hearts.
Leading 14-12, the visitors had already needed to hold their breath when Stefan Ratchford, the England full-back who switched to stand-off when injured Australian star Blake Austin was withdrawn at half-time, had a penalty from halfway to level in the 74th minute.
It fell just short. Resilient Castleford did not.
It is not the first time they have ventured to the Halliwell Jones Stadium and come away with an unlikely win, doing just that when depleted again last June. This was better still.
Warrington may have won the Challenge Cup and were second for much of the season but their woeful form over the closing weeks of Super League action has been the worst in the competition, this being their eighth loss in nine games.
As frustrations boiled over at the death, Bryson Goodwin was sin-binned for kicking the ball away and it is Castleford who, instead, deservedly press on to the second week of play-off action.
Salford Red Devils - who have signed Warrington stand-off Kevin Brown for 2020 - head to Wigan Warriors tonight and the loser of that play-off will host Tigers next Thursday.
Castleford had led 6-0 at the break following a mistake-ridden first period but Warrington, who had been dreadful, levelled just two minutes into the second period.
Ben Currie charged down Pete Matautia’s clearing kick and Warrington - who have not won the league since 1955 - finally clicked into clear.
Mamo, who came on after Man of Steel contender Austin limped off at half-time, arrived into the line and managed to get over Greg Minikin in the corner for Ratchford to level.
Rankin, though, quickly responded with a lovely worked move and Mata’utia improved.
Jame Clare denied Tom Lineham in the corner and when Mike Cooper stole from Watts, Mata’utia extend the lead to 14-6.
Warrington captain Chris Hill rumbled over in the 70th minute for Ratchford to reduce the arrears but it was not enough.
England second-row Mike McMeeken had been the latest to join Castleford’s injury-list due to a dead leg, dropping out along with fellow forward Nathan Massey.
It made Powell’s decision to drop scrum-half Jamie Ellis to the bench - and bring in rookie winger Calum Turner as part of a backline rejig - all the more brave.
That bold move, which saw Mata'utia switched back from centre to half-back, paid off, though.
That said, te opening quarter was utterly wretched and as bad an advert for Super League play-offs the competition’s chief executive, Robert Elstone, could have ever wished for.
It remained pointless but not due to any sort of immense, mind-defying defensive effort from both sides, merely because neither side could keep hold of the ball with needless unforced error after error.
Fortunately, for Castleford’s sake at least, the visitors managed to emerge from the mire to discover some clarity; they got their act together.
Rankin had already made one break down the right side before Grant Millington - the veteran prop who kept popping up on the edges - slipped Clare into space on the same flank.
Admittedly, there was no support but, after Castleford had forced a second drop-out when Daniel Smith forced Toby King back behind his own line, they did strike in the 27th minute.
Paul McShane’s delicate grubber close to the line saw Adam Milner, only just on the field as a replacement, touch down for Mata'utia to convert.
Still, three minutes later, it looked like Austin would have his moment; he jinxed through and put on his trademark step to try and beat Jordan Rankin but the Castleford full-back was not fooled.
He made the tackle and the Warrington star visibly struggled to get back to his feet, a first sign that all was not well.
Soon after, when Watts smashed his fellow Man of Steel contender as he tried getting over close to the line, it became clearer still that Austin was lame.
Daryl Clark, the elusive former Castleford hooker, thought he had stepped through to score and referee Chris Kendall agreed.
However, video referee Ben Thaler rightly ruled the ball had been held up, in all likelihood by a boot of Watts, the relentless prop who seemed omnipresent last night.
Given how tight the scoring - or lack of - was, it was no surprise that Jake Trueman attempted a drop goal but that was charged down by Clark and Warrington needed King to come to the rescue, too, as Trueman almost dummied over.
They had the edge in the end, though, and it still isn’t Warrington’s year.
Warrington Wolves: Ratchford; Lineham, Goodwin, King, Charnley; Austin, Patton; Hill, D Clark, Cooper, Currie, Hughes, J Clark. Substitutes: Philbin, Westwood, Murdoch-Masila, Mamo.
Castleford Tigers: Rankin; Clare, Minikin, Blair, Turner; Matautia, Trueman; Watts, McShane, Millington, Holmes, Clarkson, Smith. Substitutes: Milner, Cook, Ellis, O’Neill.
Referee: Chris Kendall (Huddersfield)