Jon Rahm was crowned this year's Race to Dubai winner after a birdie at the 18th hole secured the DP World Tour Championship for a second time in his career.
The Spaniard had held a six-shot lead at one stage during the final round, only for playing partner Mike Lorenzo-Vera and a fast-finishing Tommy Fleetwood to close the gap and set up a tense finish.
Fleetwood carded five birdies over the final seven holes to set the clubhouse lead at 18 under par, leaving him to sit and watch on as his 2018 Ryder Cup team-mate finished his round.
Rahm found a bunker with his approach shot to the par-five 18th but held his nerve to get over the line, chipping onto the green before rolling in a putt that not only clinched the tournament but also confirmed he will end the season as the European Tour's number one.
"I feel like I'm going to start crying," an emotional Rahm - who also triumphed at the Jumeirah Golf Estates in 2017 - told Sky Sports. "Man, it was such an up-and-down day.
"[On the] eighth tee I had a six-shot lead and I came down 18 needing a birdie to win. It was hard trying to battle out there, I kind of lost the swing a little bit."
He added: "Hard to believe that besides the putt, the first three shots on 18 is about as calm as I've been all day.
"I told myself on 18, 'How many times do you dream of having to birdie the last hole to win a tournament?'. I hit the best drive of the week, a great four iron the wind didn't take, an outstanding bunker shot and then made the putt."
Rahm's eventful score of 68 mixed eight birdies with four bogeys. He had started the week sitting third in the Race to Dubai standings, but a fourth title on the Rolex Series made sure he will finish 2019 on top.
In doing so, the 25-year-old becomes only the second Spaniard to win the European Tour's order of merit, following in the footsteps of the legendary Seve Ballesteros.
As for Fleetwood, his seven-under 65 was enough to finish alone in second place, with three putts on the final green forcing Lorenzo-Vera to settle for third.
Having led the way in the Race to Dubai going into the final event, Austrian Bernd Wiesberger slipped down the final standings after taking a share of 28th place.