Rory McIlroy fired a sensational third-round 62 to set up a Sunday showdown with American Rickie Fowler in the CJ Cup in Las Vegas.
Eight birdies and a final-hole eagle saw him move to 19 under par and briefly top of the leaderboard.
However, Fowler established a two-shot advantage at the Summit Club with a tasty round of his own.
The American finished an impressive round with a 63, with five front-nine birdies and four more coming home.
That keeps him on 21 under ahead of McIlroy, who is a further stroke clear of the trio of Abraham Ancer, Adam Scott and Robert Streb.
Shane Lowry shot an under-par 69 to move on to four under, but he remains outside the top 70.
Consecutive double bogeys at the eighth and ninth hole had seen overnight leader Kevin Mitchell fall down the leaderboard.
— Ryder Cup Europe (@RyderCupEurope) September 26, 2021
There were no such worries for Holywood man McIlroy though. He produced one of his best nine holes in some time.
He nabbed birdies on six of his seven holes between the third and ninth.
The Ryder Cupper then picked up shots at the 12th and 14th before signing off in spectacular fashion as a fine approach on 18 set up that eagle.
The former world number one has this year dropped to 14th in the rankings, leading to questions about his tactical approach.
He admitted afterward that he could not remember his last bogey-free round before this tournament, where he has now had two.
"On a course like this you're going to have stretches where you're going to play good golf and hit good shots and maybe just not hole the putts," he said.
"I played an eight-hole stretch yesterday in even par - I made eight pars in a row.
"Then today, I played nine holes in six under and all of a sudden you feel a little better about yourself."
McIlroy, Fowler and Ancer will tee off in the final group at 7.50pm, Irish time.