Seamus Power's magical run at the WGC-Dell Match Play is over after the Irishman lost to Scottie Scheffler in Saturday's quarter-finals.
Power, who earlier had beaten Tyrell Hatton 4&3 in the round of 16, was again in fine form but late mistakes cost him against world No 5 Scheffler.
Scheffler went birdie-eagle on the fifth and sixth hole to go two-up but Power fought back with a winning par on eight and a birdie on nine to tie the match at the halfway stage.
On the 12th, Power found water and conceded the hole and on the next hole Scheffler sunk a birdie from 10 foot to again go two-up. The American then closed out the match with an eagle on the par-5 16th.
Power will take what he can out of a "fun week" before then opting to sit out the Valero Texas Open ahead of his debut at Augusta.
"It's my first time playing this tournament, so overall it's been a positive appearance," he said.
"It's an unusual feeling [after you lose], but it's been a good finish in a very good field so there is something positive in that."
Scheffler, meanwhile, will not let the prospect of becoming world No 1 ahead of Jon Rahm, who had earlier lost to Koepka after 19 holes in the last 16, distract him.
"I wouldn't say I'm in a rush really to do anything out here," said Scheffler, who had earlier edged out defending champion Billy Horschel.
"I'm just enjoying myself out here and trying to do the best I can and to compete."
Also in the semi-finals is Dustin Johnson, who each day seems to be getting closer to the form that made him No. 1 in the world for longer than any other player since Tiger Woods.
Johnson had to rally from two down against Koepka in a fascinating duel between former world No. 1 players and multiple major champions.
They were all square when Johnson halved the 12th hole with a 15-foot birdie, took the lead with a 25-foot birdie putt on the 15th hole and saved another tough par on the 16th.
Johnson closed him out by driving the 18th green, forcing Koepka to aggressively try to hole a chip from left of the green that went off the putting surface into a drainage ditch.
Johnson, who won the Match Play in 2017, will face Scheffler in the semi-finals Sunday morning.
For Scheffler, more is at stake than his third PGA Tour win in his last five starts. Jon Rahm, the world's No. 1 player, lost to Koepka in 19 holes in the morning session on Saturday, meaning Scheffler can go to the top of the world ranking if he were to win the Match Play.
Elsewhere, Kevin Kisner reached the final day of this tournament for the third time, the most of anyone since it changed from single-elimination to group play in 2015. He lost in the championship match in 2018 and won the next year.
Kisner will play Corey Conners, the first Canadian to reach the semi-finals at Match Play. Conners had an easy time with Takumi Kanaya in the morning (5 and 3), and then played the 18th hole in competition for the first time all week to hold off Abraham Ancer of Mexico.
Kisner will be trying to become only the third player to reach the championship match at least three times since this World Golf Championship began in 1999, joining Woods and Geoff Ogilvy.
WGC Final Eight results
Scottie Scheffler (5) beat Seamus Power (42) 3&2
Dustin Johnson (8) beat Brooks Koepka (16) 2 up
Kevin Kisner (29) beats Will Zalatoris (24) 4&3
Corey Conners (36) beats Abraham Ancer (15) 2 up
WGC Final Four draw
Dustin Johnson (8) vs Scottie Scheffler (5)
Corey Conners (36) vs Kevin Kisner (29)