John Higgins and Ali Carter will meet in the final of the totesport.com Welsh Open at the Newport Centre.
Defending champion Carter defeated Stephen Maguire 6-3, before Higgins saw off world number one Ronnie O'Sullivan 6-4.
It was a second disappointment in as many weeks for O'Sullivan, who was beaten in a thrilling Masters final by Mark Selby two weeks ago.
O'Sullivan led 1-0 and 2-1 but a total clearance of 138 by Higgins - the top break in the tournament - enabled the Scot to level the scores again.
The world number four took the lead for the first time at 3-2 before O'Sullivan squared matters and took advantage of a Higgins slip to produce a run of 95 which gave him a 4-3 lead.
However, Higgins won a scrappy eighth frame and moved to within a frame of victory by winning the ninth.
The writing was on the wall for O'Sullivan at the start of the 10th frame when he took on a risky red, succeeding with the pot but unluckily seeing the cue ball go in the middle pocket for a foul.
It proved a costly mistake as Higgins closed out the contest - then joked of a plan to undermine his final opponent.
Earlier in the day, Carter - whose victory in this competition last season was his first ranking success - was too sharp for world number two Maguire.
A break of 80 from Carter settling the ninth frame and the match.