National League Widnes stunned Super League Castleford by 14-4 to claim a place in the last 16 of the Powergen Challenge Cup at the windswept Halton Stadium.
Australian star David Peachey grabbed a brace of tries to inspire Widnes to victory and pull off the shock of the fourth round.
The former Kangaroos full-back was too hot to handle for the visitors and it was his craft and speed that sent the Tigers crashing out of the cup at the first hurdle.
After a stuttering start to the new campaign, the Vikings finally hit top gear against the newly-promoted Tigers, but it was the steely defensive effort which ultimately won them the game.
Cas, who were not at full strength due to a catalogue of injuries, just could not force themselves across the whitewash as they chased the game for the entirety of the second half.
Widnes started the brighter of the two sides and after only two minutes were camped outside the Tigers� line as marauding props Barrie McDermott and Terry O�Connor powered forward.
But instead they had to settle for two points courtesy of Mick Nanyn�s boot as the visitors were penalised for offside.
Two minutes later Peachey raced in from 40 metres after Bob Beswick�s superb mazy run from dummy half. Nanyn added the extras to give Widnes a useful 8-0 lead.
It took the Tigers half an hour to mount their first attack and on the back of some good work from Ryan McGoldrick, loose forward Tommy Haughey barged his way over out wide.
The game was evenly poised at half-time but Peachey�s second try of the afternoon sealed it for the Vikings after he had picked up Dave Allen�s offload.
Nanyn struck his third goal to wrap things up, but then the Vikings had to keep the Tigers at bay for the final 20 minutes as they turned up the pressure on Widnes.
Heroic defending from the Vikings pack kept Paul Handforth and then Matt Whitaker out, giving the Vikings respite to mount a final attack of their own.
Mark Smith could have put the icing on the cake late on but sterling work from the Tigers prevented him from adding insult to injury.
Widnes 14 Castleford 4 Tries: David Peachey 2 Goals: Tommy Haughey 2 Goal: Mick Nanyn 3
Widnes: Peachey, Dodd, Cardiss, Nanyn, Onyango, Coyle, Durbin, T. O�Connor, Beswick, McDermott, Cassidy, Allen, Smith. Replacements: Summers, Heaton, Reid, Nash.
Castleford: Platt, Blanch, Dyer, Bird, Shenton, McGoldrick, Kain, Fa�aoso, Handforth, Whitaker, Manu, Knowles, Haughey. Replacements: Henderson, Huby, Edwards, Boyle.
Referee: A Klein (London) Att: 4,205