Brooks Koepka will become golf’s world No 1 for the first time after the three-time major winner sealed victory at the CJ Cup in South Korea.
The PGA Tour's player of the year faced a final round charge from Gary Woodland, who briefly shared the lead at the turn, but Koepka finished four shots clear of his fellow American at Jeju Island with an eight-under 64.
Koepka will displace Dustin Johnson, who did not feature in the PGA Tour event this week, when the new rankings are officially confirmed on Monday after adding his third title of the year to his major triumphs at the US Open and PGA Championship.
"To be world number one is something I dreamed of as a kid and I don't think this one's going to sink in yet," Koepka said.
"Everything I've done this year it's been working. So I don't want to change anything. Just keep improving. I'm so excited right now, you have no idea. I can't wait to go play again."
Koepka, behind fellow Ryder Cup players Johnson and Justin Rose at the start of the week, began the day with a three-shot lead but after mixing two birdies with one bogey for his front nine faced pressure from Woodland.
The 34-year-old American, who won the Phoenix Open last season, made six birdies in seven holes and four birdies in his next seven to threaten Koepka's title bid.
But Woodland bogeyed the par-three 17th and despite a closing birdie for a nine-under 63 to finish the week at 17-under, Koepka followed a gain at the 15th with a chip-in from 70-feet for birdie at the 16th before ending the week with a 25-foot eagle putt.
"I'm not somebody who's going to panic if things go the wrong way," added Koepka of his slow start.
"I felt like the one (birdie) at 15 was quite big with Gary making a charge."
Ryan Palmer also made a late charge as he birdied his last seven holes to shoot a course-record 62 and finish in a tie for third place alongside Rafa Cabrera Bello, six shots off the lead.
Ian Poulter was the best placed Brit even though he dropped eight places with a final-round one-under 71 to finish at 10-under, with Tyrrell Hatton one shot further back after a 66.
Watch live coverage of the World Golf Championships-HSBC Champions in Shanghai on Sky Sports Golf from 3am on Thursday.