Brooks Kopeka is set to become the new world number one on Monday following a four-shot victory at the CJ Cup at Jeju Island in South Korea.
The three-time major winner held a four-stroke advantage ahead of England’s Ian Poulter and Scott Piercy going into the final round on Sunday, but Koepka had a shaky start as he registered two bogeys and three birdies in his opening six holes.
However, the 28-year-old rolled in five more gains on the back nine before sealing victory with an eagle at the par-five 18th to finish on 21 under. Fellow American Gary Woodland finished second at 17 under.
“It’s a dream come true,” said Koepka after completing a final round of eight-under par 64.
“I don’t think I ever thought in my wildest dreams I’d be the best golfer in the world,” he added.
“It’s amazing to go world number one with a win. I always wanted to earn my way to number one.”
Koepka will overhaul Ryder Cup team-mate Dustin Johnson when the new world rankings are released on Monday.