Rickie Fowler produced two moments of magic to hold off late charges from Thomas Pieters, Rory McIlroy and Henrik Stenson to win his second European Tour title at the Abu Dhabi HSBC Golf Championship.
The World Number Six held a three-shot lead at the turn, but while he made seven straight pars on the back nine, McIlroy came home in 31 with an eagle at the last and Stenson came back in 32 to sit one shot behind the leader in the clubhouse.
Fowler was not to be outdone, however, and he chipped in on the 17th to open up a two-shot lead, with a par at the last enough to keep him at 16 under par and hand him a one-shot victory over Pieters, who birdied the final hole.
The 27 year old had earlier holed from a bunker for an eagle on the eighth immediately after a double bogey on the seventh cut his advantage to one on a dramatic final day at Abu Dhabi Golf Club.
The victory follows Fowler's triumph at the 2015 Aberdeen Asset Management Scottish Open and makes him just the second American to win this event after Chris DiMarco, who claimed the inaugural title in 2006.
"It's a great field that HSBC has put together here. The course is in perfect shape," said Fowler.
"It was a lot of fun today. It was a bit stressful at times. Thomas is playing well. It's fun to kind of go head-to-head with him being in the same group. We had a good time.
"It's nice to come out on top this week."
Stenson showed no ill effects from knee surgery, as he came close to completing the set of Gulf state wins after his previous victories at the Commercial Bank Qatar Masters, the Dubai Desert Classic and the DP World Tour Championship.
It was another close call for McIlroy who had to make do with a share of third after finishing second here in four of the last five years, while Pieters missed out on a third European Tour title after claiming two wins in three weeks last summer.
World Number One Spieth finished with a 68 to lead the group at 11 under alongside Byeong Hun An, Alejandro Cañizares, Branden Grace, Joost Luiten and Marcel Siem.
Ian Poulter had looked the most likely challenger to Fowler in the early stages, as he opened with a pair of birdies and then holed a lengthy putt on the fourth to get to 12 under and within striking distance.
But Fowler, who had made three gains in seven holes as he completed his third round in the morning, opened birdie-birdie himself to get to 15 under and at one point held a four-shot lead over the field.
That then all looked like it was going to disintegrate on the seventh as Fowler surrendered two shots.
It seemed like he had got a stroke of luck as he avoided the water off the tee, but he flew his shot from a waste area over the green and then needed two putts to drop to 13 under.
Cañizares then holed a long putt from the fringe on the tenth to cut the gap to one shot before Fowler responded in spectacular style.
Just when it looked like the pack were closing in, he holed his third shot on the par five eighth out of the bunker to get the two shots straight back and open up a three-shot cushion.
"On seven I made a bad swing, so kind of deserved a little bit of a penalty there," he said. "I got a bit of a bad break having a boulder underneath the ball there. So nothing I can really do about that.
"And I almost made four, which would have been amazing.
"My caddie responded with, 'you know, golf is funny that way'. I said, 'well, you flip them, two pars in a row'."
Pieters began the third round three shots behind Fowler and he picked up shots on the sixth and eighth, with further gains on the tenth and 13th moving him to within a shot of the lead as Fowler went on that run of pars.
Stenson had turned in 35 thanks to birdies on the first and eighth with a bogey on the seventh. He picked up another shot on the tenth, but came alive from the 15th as he finished birdie-par-birdie-birdie to set the target at 14 under.
McIlroy was six shots off the lead as he stood on the 12th tee after three bogeys and two birdies but he birdied the 12th and 13th before a brilliant chip-in on the 16th. A stunning approach to the last and a curling putt then gave him his second eagle of the week on that hole to put the pressure on Fowler.
For the second time that day, the Ryder Cup star responded magnificently, deftly chipping from the rough on the right of the green on the 17th to get to 16 under and keep Pieters at bay up the last.
Spieth had been enduring an indifferent week by his lofty standards and was level par on the 12th tee but he made three consecutive birdies and finished with another gain on the last to ensure a share of fifth.
Cañizares had been four under for the day when he birdied the tenth but he dropped a shot on the 14th on the way in, while Siem had a single bogey in his 67.
Luiten had one bogey and one birdie in a 72 while An picked up four shots in the final six holes to sign for a 71, the same score as Grace who had four birdies and three bogeys.