Rory McIlroy was beaten in the WGC-Dell Technologies Match Play Championship semi-final by American Cameron Young in a dramatic sudden-death extra hole.
The world number three looked to be in control of the match but Young squared it on the 18th green and then snatched victory with birdie on the 19th hole.
Young will play Sam Burns in the final after he upset world number one Scottie Scheffler in a similarly tight match, settled on a third extra hole.
The final is played later on Sunday.
The two surprise results denied the tournament the McIlroy-Scheffler final many anticipated throughout the week and for much of their semi-finals.
McIlroy was two up with three holes to play but 15th seed Young made birdie on 16 before holing a seven-foot putt on the 18th to square the match.
The Northern Irishman failed to capitalise on a fortunate break when the pair replayed the 12th hole – his wayward tee shot found a flat lie while Young’s landed up against the edge of the bunker – and then missed a 10-foot putt after Young, who has never won on the PGA Tour, had made his.
Scheffler was three down early on after his good friend Burns started with three birdies but responded with four of his own in five holes which had him two up by the 10th.
But in a fine match, 13th seed Burns levelled again on the 16th and put himself in front with a perfect tee shot on the par three 17th, only for defending champion Scheffler to birdie the 18th to tie the match.
Scheffler had won his last 10 matches in the tournament but, after they both birdied the 19th hole and made par on the next, a 15-foot putt on the 21st proved decisive from Burns.
Scheffler and McIlroy will meet in the third-place play-off.