Danny McGuire's second try, seven minutes from the end of a classic Challenge Cup semi-final, sent Leeds to Wembley. It means that a generation of players who have achieved so much together will now have the opportunity to fill in their one unticked box in three weeks' time.
After a stirring contest in which the Rhinos seemed to have lost their way a couple of times, they were rescued by McGuire's poaching instincts. "He's the best I've seen at anticipating when chances are going to come up," said his coach, Brian McClennan. "But I'm just full of admiration for the players' spirit and the way they kept fighting back.
"One thing you know about this Leeds team is that they are never, ever going to give up."
This semi-final between such long- established rivals looked so finely balanced that the bookies' odds shifted appreciably with the news that Leon Pryce was out of Saints' side with a neck injury and that Greg Eastwood had recovered sufficiently from a knee problem to take his place on the Leeds bench.
Despite that, though, Saints made the stronger start and crossed the try-line after only two minutes, only to have Francis Meli's score ruled out for Chris Flannery's knock-on. It was Leeds who drew first blood when Scott Moore was penalised for a late tackle on Kevin Sinfield and the Leeds captain dusted himself off to land the kick. The Rhinos extended their lead when the outstanding Keith Senior offloaded the ball and Brent Webb skimmed the fingertips of Jamie Foster, who had left his wing, to send Ryan Hall over for a try which Sinfield then converted from the touchline.
So far, so good, but Leeds completely undermined that handy first-quarter lead with individual errors. Luke Burgess lost the ball in a tackle and Saints seized their chance, with Paul Wellens twisting his way over from Moore's pass.
The arrival of Keiron Cunningham from the bench had given Saints a definite boost and he scored a characteristic try by powering his way over from dummy-half.
Worse still for Leeds, Eastwood attempted an ill-advised fingertip flick-on and succeeded only in presenting the ball to Meli for a stroll to the try-line, with Foster adding his third goal.
Trailing 8-18 at the break, Leeds soon hit back with Hall's second try but Saints replied when Matt Gidley's burst of acceleration took him over.
Then, just before the hour, McGuire began to emerge as the game's major influence as he claimed his 200th Leeds try from Senior's dummy-half run, after juggling the ball three times on his fingertips. Leeds got their noses back in front four minutes later when Saints got caught out again in that area and Danny Buderus's dart and back-handed pass sent Brent Webb away.
Saints refused to buckle, though, and regained the lead when James Graham crashed over from Cunningham's pass. But then Jamie Peacock, who had been bashing his head against a wall all day, stood in a tackle, slipped the ball to McGuire and the Rhinos were on their way to Wembley.
"It's something we've been talking about," said an admiring McGuire, the man of the match, afterwards. "He's superhuman, is JP."
"I couldn't ask much more of them. They did their darnedest," said the Saints coach, Mick Potter, who refused to blame the absence of both his regular half-backs, Pryce and Kyle Eastmond, for the defeat.
"We were capable of winning the game and we were in a winning position several times, but the other team came up with the right plays at the right times".
Leeds Webb; Smith, Delaney, Senior, Hall; McGuire, Burrow; Bailey, Buderus, Peacock, Jones-Buchanan, Clarkson, Sinfield. Substitutes used Leuluai, Eastwood, Diskin, Burgess.
St Helens Wellens; Foster, Gidley, Meli, Gardner; Wilkin, Moore; Graham, Roby, Hargreaves, Flannery, Ashurst, Magennis. Substitutes used Cunningham, Puletua, Clough, Emmitt.
Referee P Bentham (Warrington).
Tries: Cunningham, Wellens, Meli, Gidley, Graham
Goals: Foster 4
Tries: Hall 2, McGuire 2, Webb
Goals: Sinfield 6