Leigh Leopards beat St Helens 12-10 to reach the final of the Challenge Cup, having only returned to the Super League this year.
It's the first time Leigh have reached the Challenge Cup final in more than 50 years, producing a heroic defensive performance to sink the defending Super League champions and book their place in the Wembley final, their first since 1971.
Adrian Lam's men held their nerve in frantic final exchanges which saw Jonny Lomax cross to give Saints hope only for Tommy Makinson to miss an 79th-minute conversion that could have forced golden point extra time.
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Leigh had trailed 8-0 after a bruising first period in which they were almost constantly on the back foot, before tries early in the second half from Oliver Holmes and Zak Hardaker turned the match on its head.
The win signals an amazing achievement for the Leopards, who less than 12 months ago were lifting the 1895 Cup for second and third-tier teams at Tottenham.
Since then the club's trajectory has been remarkable and they headed to the Halliwell Jones Stadium in Warrington sitting in an improbable second place in the Betfred Super League with 12 wins from 13 matches.
Showing all the resolve that has turned their first season back in the top-flight into such a success, Lam's men survived near-constant pressure in the opening 40 minutes but Saints had only Joey Lussick's converted try to show for their efforts.
Lussick, in for the absent James Roby and potentially playing his last game for the club, had been a dominant presence in the early exchanges and pounced over from dummy half in the 18th minute to give his side the lead.
His outrageous 40/20 then set up another spell of Saints pressure less than five minutes later but Josh Charnley raced across to intercept a diving Makinson in the corner for what arguably proved to be the game's pivotal moment.
Leigh looked re-energised for the second period and hauled themselves level within three minutes, capitalising on a penalty deep in Saints territory when Lachlan Lam's crisp offload sent Holmes scampering 20 metres to touch down.
Edwin Ipape came up inches short as Saints struggled to contain the Leigh momentum, and within five minutes the Leopards had the lead when Hardaker got on the end of Lam's kick to touch down his side's second try.
Saints responded in typical fashion by pummelling the Leigh line but suffered a further blow on the hour mark when Sione Mata'utia was sin-binned for a late hit on Ben Reynolds, who extended his side's lead to 12-6 from the resulting penalty.
Benefiting from a period of repeat sets, Saints stretched the Leigh defence to breaking point with Konrad Hurrell adjudged to have been held up, then Lomax fumbling a golden opportunity after a pass from Lussick.
With the tension mounting, Saints' stand-in captain made amends with less than two minutes left on the clock when he threw a dummy and burrowed in between two Leigh defenders to give his side hope.
But Makinson saw his difficult kick from the right stay just the wrong side of the posts, and after playing out a further pressure-filled minute, Leigh were left celebrating one of the greatest wins in their history.