Jason Day ensured his return to the top of the world rankings after he booked a semi-final clash against Rory McIlroy at the WGC-Dell Match Play in Texas.
Day, who almost withdrew from the competition after straining his back towards the end of his win over Graeme McDowell on day one, produced a strong back-nine performance to earn a 3&2 victory over Brooks Koepka.
The Australian was always in control of his last-16 clash with Brandt Snedeker on Saturday morning in Austin before wrapping up victory on the 16th, and he took that momentum into his afternoon encounter with Koepka.
A birdie from seven feet at the opening hole gave Day an early advantage, although Koepka levelled against the run of play at the fifth when he holed from 25 feet for birdie and Day's putt for the half from four feet stayed out.
Day found trouble off the tee at the next and was unable to match Koepka's birdie-four, but the 2014 champion got back on track with a 13-foot putt for a win at the eighth before he reclaimed the lead when he converted a neat pitch to seven feet at the 10th.
Koepka made a mess of the long 12th and was forced to concede the hole with Day lining up a 12-foot putt for eagle, and the American found himself three down with three to play when he missed from five feet at the 15th.
Both players got into a tangle at the par-five 16th, but Day managed to salvage what proved to be a match-winning par that guaranteed he would replace Jordan Spieth as world No 1 when the rankings are updated on Monday.
"It's not so much about the No 1 rank that really gets me excited, it's more so the journey and the process that it's taken," said Day. "To get to the top of your sport takes a long time and so for me it's that delayed gratification.
"To be No 1 in the world is fantastic, and the next step is try to get into tomorrow's round. I know I have a tough one against Rory and I'm looking forward to it.
"It's been a bit of an up and down week, especially emotionally. It's been quite amazing to be able to start the week and not really thinking I'm going to be able to play with what happened on Wednesday. And now I'm No 1 in the world on Saturday. It's a strange feeling, but I'm glad I stuck it out."