Sanchez celebrates his controversial opening goal
A Champions League death by a thousand cuts finally brought Leeds' European adventure to an end in Spain.
David O'Leary's brave young side had bounced back from a number of cruel setbacks throughout the competition.
But when Juan Sanchez opened up the tightest of semi-finals by clearly using an arm to turn home Gaizka Mendieta's 15th-minute cross, Leeds had suffered one setback too many.
O'Leary's players were furious that referee Urs Meier failed to rule out the crucial opener and were reeling again when the striker scored a magnificent second goal early in the second half.
Mendieta completed what proved to be a comfortable victory as Valencia eased through to their second successive Champions League final.
Leeds' misery was completed when Alan Smith's reckless last-minute challenge on substitute Vicente results in a red card.
But it could all have been so different.
Despite a nervy opening five minutes, Leeds settled well and were competing comfortably before Valencia's controversial opener.
Mendieta's searching cross perfectly dissected defence and goalkeeper and Sanchez dived headlong to turn the ball home.
Whether Sanchez made contact with his arm was not in question. The question of intent as he dived headlong to reach the ball may have persuaded the referee to ignore the contact.
Either way, it was another cruel twist of the knife for Leeds in a competition which has dealt them one cruel blow after another.
Goalscorer Sanchez was the player involved in the alleged stamping incident which ruled Lee Bowyer out of this crucial second leg clash.
The goal also brought back painful memories of Raul's blatant handball goal in the clash with Real Madrid.
The difference is that the game in Madrid counted for nothing as both sides had already qualified for the quarter finals.
Sanchez's strike was infinitely more important, though Leeds knew they still only needed one goal to progress on the away goals rule.
At first, it seemed as though Leeds' indignation would translate into frustration, but they responded with a steely determination to carve out that crucial opening.
David Batty, making his 500th club appearance, also shot at the keeper after superb work down the left by Mark Viduka as Leeds began to expose some cracks in one of Europe's tightest defences.
But while Valencia were showing minor cracks, yawning holes in the Leeds defence in the opening minutes of the second half allowed the home side to clinically book their place in the final.
Precisely 100 seconds after the restart, Sanchez galloped into acres of space before unleashing a clinical left-foot drive into the bottom right hand corner of Martyn's net.
While the arguments will rage long and hard over his opener, no-one can take away the quality of his crucial second strike.
Six minutes later, Mendieta produced a carbon copy strike to rub salt into Leeds' gaping wounds.
Another left-foot shot, on the same spot 20 yards out from which Sanchez had struck, again gave Martyn no chance.
In truth, it was that 10-minute opening spell in the second half, and not Sanchez's controversial opener, which ultimately brought about Leeds' downfall.
There also seemed little hope of a Leeds revival, so deflated were David O'Leary's side by that stage.
Instead, Sanchez came closest to another goal, the striker denied a hat-trick by the width of a post.
Crucially though, Sanchez was well aware he had already got his hands on the match ball.
Valencia: Canizares, Angloma, Ayala, Pellegrino, Aurelio, Albelda, Mendieta, Aimar, Kily Gonzalez, Carew, Sanchez. Subs: Palop, Deschamps, Djukic, Zahovic, Alonso, Angulo, Vicente.
Leeds: Martyn, Mills, Ferdinand, Matteo, Harte, Bakke, Dacourt, Batty, Kewell, Viduka, Smith. Subs: Robinson, Kelly, Woodgate, McPhail, Wilcox, Burns, Maybury.
Referee: Urs Meier (Switzerland)