England's Justin Rose claimed a fourth USPGA Tour win at the WGC-Cadillac Championship at Doral, in Florida.
The Hampshire golfer stood three shots back at the start of play, trailing overnight leader Bubba Watson.
But, with Watson fading, world number one Rory McIlroy's late charge falling short and Tiger Woods retiring with an Achilles injury, Rose held his nerve.
A final round two-under 70 was enough to win by a shot from Watson, who missed a 10-foot birdie putt at 18.
That followed a fantastic recovery from a wayward drive down the last by Watson, from almost the same spot where Rose had bogeyed to open the door for the American 15 minutes earlier.
"There's been a lot of hard work going on in my game," said Rose. "And days like this make it all worthwhile.
"I really enjoyed playing with Bubba Watson for three days. And going out one group ahead of the leaders is never a bad thing.
"But the two shots he hit into 18 had me sweating."
Rose's victory matches Tony Jacklin and Luke Donald's four wins on American soil, meaning that Sir Nick Faldo, with nine titles, is the only Englishman who can boast more successes in the United States.
Watson had been three clear when he resumed but, after a two-putt birdie on the first, he began to struggle.
The American had three bogeys in a row from the third - a hole which had earlier seen Sergio Garcia put four balls in the water on the way to a 12 - as he turned in a damaging outward 39.
Keegan Bradley, who won the US PGA Championship last August in his first major, took advantage of Watson's woes, leading by two shots after seven holes, having eagled the first. But he took six at the long eighth and then four-putted from just off the 10th green for another bogey, coming home in 42.
Rose's fellow Englishman Luke Donald finished on 12-under in a tie for sixth - his first top 10 finish of the year.
McIlroy, officially the world's best player after winning the Honda Classic, put himself in contention for a second successive victory but had to settle in the end for a five-under 67.
That earned him a tie for third as he now takes three weeks off to prepare for Augusta.