Graeme Dott took full revenge on Ronnie Sullivan to reach his second World Championship final and clinch a meeting with Peter Ebdon at the Crucible Theatre.
Dott had been thrashed 18-8 despite leading 5-0 at one juncture when he met O'Sullivan in the 2004 final as a rank outsider.
But a dramatic third session, in which he won all eight frames against an out-of-sorts O'Sullivan, was the catalyst for his 17-11 triumph over the Rocket.
O'Sullivan had appeared agitated during Friday's two sessions - culminating in him needing a 15-minute break to replace the tip on his cue - although he was still in contention overnight at 8-8.
But his game completely went to pieces when play resumed on Saturday morning and he was a dejected figure by the time he shook hands with a triumphant Dott just one frame from victory.
It was the third time that O'Sullivan has lost all eight frames in a season at Sheffield with John Parrott in 1994 and John Higgins four years later inflicting on him the same misery.
O'Sullivan constantly failed to convert half chances, did not look comfortable with his long potting game and towards the end of the session appeared resigned to his fate.
Credit should be given to Dott who has produced rock solid-snooker over the three days against O'Sullivan and clearly has the temperament to handle the pressure cooker situation of a world semi-final.
But even he must have been stunned by the stream of errors from O'Sullivan which handed him chance after chance which the Scot gratefully accepted.
At least O'Sullivan came out in a positive frame of mind to confront a seemingly hopeless task in the evening session of having to win all nine frames.
Two breaks of 60 won O'Sullivan the opening two frames and a run of 38 proved sufficient in frame 27 to reduce his deficit to 16-11 and enabled him to regain some pride.
A tense bout of play in the next culminated in O'Sullivan missing the final blue when leading 68-51 before Dott eventually edged home by potting the final black.