Jon Rahm fired nine birdies and an eagle in a 10-under par 63 on Sunday to surge past faltering Collin Morikawa and win the US PGA Tour Tournament of Champions by two strokes.
Rahm trailed third-round leader Morikawa by nine after a bogey at the first hole, and two-time major winner Morikawa had pushed his six-shot overnight lead to seven after his third birdie of the day at the sixth.
Spain's Rahm, however, poured it on and Morikawa cracked, Rahm capturing his eighth US PGA Tour title with a 24-under par total of 265 on the par-73 Plantation Course at Kapalua in Hawaii.
Morikawa, whose bogeys at the 14th, 15th and 16th were his first of the week, carded a one-under par 72 for 25-under 267.
Rahm said he'd never have dreamed after his opening bogey he'd walk off the 72nd green with a three-shot lead.
"At that point it's not like winning is really that in mind," he said.
"You've just got to get to work and start making birdies, and that's what I did."
He drained a 12-footer for birdie at the second, then birdied the fourth, fifth and sixth before punctuating his outward run with a birdie at the ninth.
"That stretch of four through six, birdying nine, allowed me to get into a rhythm," Rahm said.
But the real push came later, when he picked up five strokes in four holes with birdies at the 12th, 13th and 14th and an eagle at the par-five 15th.
The run started with a two-foot birdie at 12. After a 13-footer at 13 he tapped in at 14.
After he rolled in an 11-foot eagle putt at 15 to get within one stroke of Morikawa, "that's when I started thinking about it," Rahm said.
He couldn't get a 10-foot birdie attempt to drop at 16, and he got a scare when he missed the green at 17 but got up and down for par before closing with a birdie at the par-five 18th.
Morikawa couldn't respond.
"Sadness," said the 25-year-old American, who was looking for his first victory since he won his second major title at the 2021 British Open at Royal St. George's.
"It sucks," he said. "You work so hard and you give yourself opportunities and just bad timing on bad shots and it kind of added up really quickly."
Morikawa was in a greenside bunker at the 14th, made a poor shot out and was unable to make the 10-footer to save par. He needed four shots to reach the green at the par-five 15th and missed an eight-footer and made bogey from the fairway at 16.
Morikawa said the result was more painful than his 2021 Hero World Challenge finish, where he took a five-shot lead into the final round with a chance to claim the number one ranking but ended up tied for fifth.
"I don't know what I'm going to learn from this week," said Morikawa, who had appeared to be reaping the rewards of recent work with both a putting specialist and short-game coach. "It just didn't seem like it was that far off."
Rahm came away with the win a year after his scorching 33-under par total at Kapalua left him a stroke behind winner Cameron Smith, whose 34-under set a new record for the lowest 72-hole score in relation to par US PGA Tour history.
He also scooped a $2.7 million winner's prize from the $15 million purse — boosted this year in the first of the PGA Tour's "elevated events" for 2023 featuring increased purses and promises of top fields in response to the Saudi-funded LIV Golf League.
World number two Scottie Scheffler missed a chance to supplant Rory McIlroy atop the world rankings.
The reigning Masters champion needed to finish in a two-way tie for third or better and was in the vicinity early in the round.
But his three-under par 70 left him tied for seventh on 21-under.
Americans Tom Hoge and Max Homa shared third on 269, Hoge carding a 64 and Homa a 66.