Bradford, holders of every trophy available to them at kick-off time, lost their grip on one of them against the side that has so often been their Challenge Cup nemesis.
St Helens produced a stirring performance to continue their recent tradition of beating the Bulls in the cup, just as they have done in three finals over the last eight years.
Inspired by a commanding display at scrum-half from Sean Long, they were never behind and finished as relatively comfortable winners of a game that their coach, Ian Millward, had predicted in advance would produce one of the Cardiff finalists in May.
Saints rocked the Bulls from the start with their blend of uncompromising defence and intelligent use of the ball.
"They were quicker than us in every aspect of the game,'' admitted the Bradford coach, Brian Noble, and that showed from the early stages when Nick Fozzard's offload sent Mark Edmondson racing away for the game's first try.
Long intercepted from Lee Radford for the second and his three goals, against one from Paul Deacon, gave Saints a 12 point lead.
Bringing back Deacon ahead of schedule after an eye operation looked a risk and it was one that was never fully justified, although he did score the try from Aaron Smith's pass that brought Bradford back in to it before half-time.
The Bulls were still well short of the compelling form they showed against Penrith Panthers and Wigan in their previous two games, but if Paul Johnson had got over the line 10 minutes into the second half they could have mounted a fight back.
Instead, a copybook tackle from Paul Wellens took him in to touch and Bradford were never truly in with a chance again.
Fittingly, it was Lee Gilmour, who left Odsal for Saints amid some acrimony this winter, who sealed their fate. He ran from deep to take Willie Talau's pass for the clinching try and the lead was stretched further when Martin Gleeson reached over the line after Long had given him the ball.
Radford showed both determination and smart footwork to get one back for the Bulls, but it was too late and Paul Sculthorpe's late effort only underlined Saint's superiority.
"They're worthy world champions," said Millward, with reference to the vanquished Bulls earlier win over the Australian champions Penrith. "They deserved that, but they're out and we're through. We're really keen to get to Cardiff now. Nothing less than the final will be good enough.''
Bradford: Withers, Vaikona, Kohe-Love, Johnson, Vainikolo, Pryce, Deacon, Anderson, Smith, Fielden, Radford, Peacock, Langley. Substitutes used: Reardon, Bridge, Vagana, Parker.
St Helens: Wellens, Albert, Gleeson, Talau, Feaunati, Hooper, Long, Fozzard, Cunningham, Edmondson, Bennett, Gilmour, Sculthorpe. Substitues used: Higham, Mason, Joynt, Hardman.
Referee: K Kirkpatrick (Warrington).Reuse content