Britain's Tyrrell Hatton, in only his second tournament since right wrist surgery, held off Australian Marc Leishman to win his first PGA Tour title on Sunday at the Arnold Palmer Invitational.
The 28-year-old Englishman made a double bogey at 11 but closed with seven tension-packed pars to finish a two-over 74 final round and complete 72 holes at brutal and windy Bay Hill on four-under 284 to edge the Aussie by a stroke.
"To hold on and win here, such an iconic venue, I'm just over the moon," Hatton said.
While world number one Rory McIlroy and other contenders faded on the famed Orlando layout, Hatton rose to the challenge of last-pair playing partner Leishman to collect the victory in his 60th PGA start.
Hatton has also taken four European Tour victories, the most recent at last November's Turkish Airlines Open, just before he underwent surgery.
"It's hard to explain. It's just an incredible feeling," Hatton said. "Such a tough day today. Felt like I was playing myself out of it when I made double at 11."
Leishman, the 2017 Bay Hill champion who won his fifth PGA title in January at Torrey Pines, shot 73 to finish on 285 with South Korean Im Sung-jae third on 286 and American Bryson DeChambeau fourth, and the only other player under par for the week, on 287.
Not since the 2014 WGC Mexico event had five or fewer players cracked par for 72 holes outside a major.
McIlroy stumbled to a 76 to share fifth on 288 with New Zealand's Danny Lee and Americans Keith Mitchell and Joel Dahmen.
Hatton led Leishman by two shots when the day began but found a fairway bunker with his first tee shot and missed an eight-foot par putt to open with a bogey, then made another at the fifth after plunking into greenside sand.
But Hatton responded to the pressure with a tee shot to two feet and birdie tap-in at the par-3 seventh and a nine-foot birdie putt at the par-4 eighth as he made the turn two ahead of Im.
Hatton bounced his tee shot at 11 into the water, sent his third over the green, pitched to the fringe 33 feet from the cup and made a six-foot double bogey putt.
Im, who made bogey at 11 but birdied the par-5 12th, briefly shared the lead but his double bogey at 13 left Hatton alone at the top again.
Leishman made a 16-foot par save at 11 and reached the green in two at the par-5 12th to set up a tap-in birdie and close within one of Hatton.
At 13, Hatton was into the deep left rough but blasted over trees and water onto the green saved par.
Leishman missed a 14-foot par putt at the par-3 14th, falling two back, but birdied the par-5 16th to close within one again. He was just left on a 34-foot birdie putt at the par-3 17th but each man parred to send the drama to 18.
Leishman left a 70-foot birdie putt six feet short, Hatton rolled a 25-footer for birdie to 2 1/2 feet and each man sunk a final par putt to give Hatton the triumph.
Four-time major winner McIlroy, who defends at the Players Championship next week, managed a sixth consecutive top-five finish this season despite finding only 4-of-14 fairways on his way to a closing 76.
A pair of double-bogey disasters doomed McIlroy's bid for a second Bay Hill crown in three seasons.
The first came at the par-5 sixth when the 30-year-old Northern Ireland star found the right rough and a greenside bunker, then blasted over the back of the green into rocks. A penalty drop and pitch followed and he two-putted from inside seven feet.
At the par-4 ninth, McIlroy hooked his tee shot left out of bounds, found the left rough and a greenside bunker and blasted out from 85 feet to three feet and salvaged a double, making the turn six adrift.
Leading scores after Sunday's final round of the PGA Arnold Palmer Invitational at Bay Hill in Orlando, Florida (USA unless noted, par-72):
284 - Tyrrell Hatton (ENG) 68-69-73-74
285 - Marc Leishman (AUS) 71-69-72-73
286 - Im Sung-jae (KOR) 70-69-74-73
287 - Bryson DeChambeau 73-71-72-71
288 - Keith Mitchell 68-75-74-71, Joel Dahmen 72-72-73-71, Danny Lee (NZL) 71-67-75-75, Rory McIlroy (NIR) 66-73-73-76
289 - Matthew Fitzpatrick (ENG) 70-75-75-69, Collin Morikawa 70-71-75-73, Kang Sung (KOR) 69-68-78-74, Harris English 69-70-74-76
290 - Talor Gooch 67-80-72-71, Charley Hoffman 70-73-74-73
291 - Patrick Reed 70-70-80-71, Scottie Scheffler 67-74-75-75, Tom Hoge 70-70-76-75
292 - Danny Willett (ENG) 71-71-77-73, Rickie Fowler 71-70-77-74, Brendon Todd 68-72-78-74, Jason Kokrak 71-75-72-74, Dylan Frittelli (RSA) 71-72-74-75, Christiaan Bezuidenhout (RSA) 68-72-73-79
293 - Jimmy Walker 73-69-89-71, Adam Long 69-74-78-72, Beau Hossler 73-72-76-72, Zander Schauffele 73-74-72-74, Matt Wallace (ENG) 69-73-76-75, Troy Merritt 71-72-75-75, Max Homa 72-75-70-76, Patrick Rodgers 73-70-73-77