Norway's Viktor Hovland made back-to-back eagles down the stretch on Sunday to hold off American Scottie Scheffler and win the Hero World Challenge after 54-hole leader Collin Morikawa unravelled.
Ninth-ranked Hovland began the day six strokes adrift but fired a six-under par 66 to end 72 holes on 18-under 270 at the Albany resort in the Bahamas.
That was good enough for a one-stroke victory in the 20-man invitational hosted by Tiger Woods.
"It's really cool," Hovland said. "Being Tiger's event, that's incredible to be a part of and especially to win it.
"I haven't really done all that well in these limited field events so hopefully that's going to change."
The 24-year-old from Oslo matched the best final-round fightback by any Challenge champion.
"I didn't think a win was going to be very plausible," Hovland said. "But I know this golf course is tricky. You can make a lot of birdies and you can make up a lot of ground but it's very easy to make bogeys and doubles.
"I knew if I put a good score up there you never know what's going to happen."
Hovland, who defended a US PGA title last month at Mayakoba, also won a European Tour title this year in June at Munich.
He took full advantage of a collapse by reigning British Open champion Morikawa, who squandered a five-stroke lead with a chance to become world number one by winning.
The second-ranked American, who got engaged earlier in the week, matched the Challenge futility mark of Charley Hoffman, who squandered a five-stroke lead in the final round in 2017.
Scheffler birdied six of the last eight holes to finish second on 271 after a second straight 66 with Americans Sam Burns and Patrick Reed on 273 and Morikawa shooting 76 to match Justin Thomas in fifth on 274.
Burns, Hovland and Reed shared the lead at 15-under with Morikawa and Scheffler two back when the back-nine battle began, but bogeys by Reed at 10 and Burns at 11 left the Norwegian in the lead alone.
Hovland, who reeled off three consecutive birdies starting at the par-5 sixth, birdied the par-5 11th to stay in front after Burns birdied 12.
Hovland missed the green at the par-3 12th and made bogey, falling into a share of the lead with Burns, whose triple-bogey disaster at the par-4 14th doomed his bid.
Scheffler, who began the day seven adrift and made triple bogey at the fourth, birdied the par-5 15th for his fourth birdie in five holes to grab a share of the lead.
But Hovland answered with his third eagle of the week at 14, blasting the ball out of a bunker, across the green and into the cup to seize a two-shot lead.
Scheffler birdied 16 and the par-3 17th to again share the lead but Hovland answered by sinking a 20-foot eagle putt at the par-5 15th to restore his two-stroke advantage.
Hovland birdied 16 for a three-stroke edge and was able to close bogey-bogey and still secure the triumph.
Morikawa, who began the day with a five-stroke lead, hooked second shots left into bushes for lost balls at the par-4 fourth and par-5 sixth, making double bogeys on each to fall two adrift of Burns and set the stage for the back-nine shootout.
Sweden's Henrik Stenson and American Jordan Spieth, in the first pairing, were handed two-stroke penalties for playing from the wrong tees at the par-5 ninth. They instead played from the adjacent 17th tee.
Organizers switched the tees for the final round after having warned players they might make such a move.
"I've never experienced that before," Spieth said. "There was a sheet saying there was a new yardage on 17 but there was nothing about number nine."
"We didn't pay attention being first out and just motoring along," Stenson said. "A little note on the tee box would have been helpful."
270 - Viktor Hovland (NOR) 68-69-67-66
271 - Scottie Scheffler 71-68-66-66
273 - Sam Burns 71-65-68-69, Patrick Reed 68-69-67-69
274 - Justin Thomas 67-72-71-64, Collin Morikawa 68-66-64-76
275 - Tony Finau 68-66-70-71, Daniel Berger 66-69-69-71
277 - Justin Rose (ENG) 71-70-70-66, Tyrrell Hatton (ENG) 69-67-71-70, Brooks Koepka 67-67-69-74
278 - Xander Schauffele 70-70-70-68, Matt Fitzpatrick (ENG) 71-70-68-69
280 - Abraham Ancer (MEX) 66-73-72-69, Harris English 75-70-63-72, Bryson DeChambeau 69-64-73-74
281 - Webb Simpson 67-72-71-71
282 - Rory McIlroy (NIR) 66-71-75-70
289 - Henrik Stenson (SWE) 72-75-70-72
294 - Jordan Spieth 71-72-75-76