Veteran Jimmy White was beaten 4-3 by Ronnie O'Sullivan after their Champion of Champions match in Coventry went to a deciding frame.
The 57-year-old, a World Championship runner-up on six occasions, won the first three frames before the five-time Crucible champion bounced back.
White, winner of the World Seniors title in August, missed a crucial red when 29 ahead in the final frame.
O'Sullivan returned later to beat John Higgins 6-3 and book a semi-final spot.
He will face Neil Robertson in the last four on Friday, while Mark Allen takes on Judd Trump in Saturday's other semi-final.
The meeting of snooker greats White and O'Sullivan attracted a sell-out crowd at the Ricoh Arena.
And they looked set to witness a major upset as White hit a 56 break in taking the opener, and then won the next two frames.
World number three O'Sullivan, 43, pulled the score back to 3-2 but White was 38-0 ahead in the sixth frame before an unfortunate kick on the black helped turned the match around.