Rory McIlroy lost his grip on the WGC-Dell Match Play title as he was beaten one up in the semi-finals by Jason Day.
Australia’s Day, 28, whose run in the tournament has taken him back to world number one, will play Louis Oosthuizen of South Africa in the final.
Defending champion McIlroy, 26, was one up on Day at the turn at the Austin Country Club in Texas.
But Day, the 2014 winner, won three of the next four holes and despite winning the 14th, McIlroy could not get closer.
World number three McIlroy just failed with a long putt on the 17th to tie the scores.
He was given another chance by Day’s errant tee shot on the last but could not capitalise to take the match into extra holes.
Oosthuizen, 33, beat Rafa Cabrera Bello of Spain 43 in the other semi-final.
The championship match will follow a third-place play-off later on Sunday.