Dubai - A back nine meltdown by Justin Rose on Sunday handed the Race to Dubai title to Tommy Fleetwood and the $8 million DP World Tour Championship to Jon Rahm.
The English world No 6 was leading by one shot after 11 holes of blemish-free golf, and with Fleetwood struggling to post a good score it looked like the 37-year-old was set for a double celebration at the end of the day.
However, things changed dramatically on the back nine. Rose, winner of tournaments in China and Turkey in his last two starts, dropped shots on the 12th, 14th and 16th holes.
Spain's world No5 Rahm seized the opportunity and birdies on the 14th and 16th holes saw him snatch the lead in the tournament.
Rahm, who closed with a five-under par 67, finished on 19-under par 269.
Rose could have still denied Fleetwood by making an eagle on the 18th hole but his effort slid past the cup, handing the European No1 honour to his 27-year-old compatriot.
Rose needed to finish at least solo fourth, but the ensuing birdie only gave him a tied fourth place at 17-under par.
Fleetwood finished tied 21st at 11-under par after a round of two-over 74.
Ireland's Shane Lowry (63) and Thailand's Kiradech Aphibarnrat (67) were tied for the second place at 18-under par, while Masters champion Sergio Garcia (65) and the South African duo of Dean Burmester (68) and Dylan Frittelli (69) were tied fourth at 271 alongside Rose.
A delighted Fleetwood, who finished the season on 5,420,529 points and collected the $1.25 million bonus pool cheque, said: "It's the biggest day of my career for sure.
"The emotions were difficult on me because I don't trust computers, so even when everything had finished, it was so difficult to get up or down. Then I felt for Justin a lot, because I'd see him when he came in. But he was so gracious and that shows a lot about his character.
Rose was left scratching his head after the finish after playing brilliant golf for three-and-half days.
"I did hit the wall a bit today. Front nine was beautiful. I was playing great golf and I felt in complete control. The bogey at 12 seemed to slow all the momentum. Front that point it was a bit of a grind," said the 2016 Olympic gold medalist.
"The other guys seemed to do what they needed to do down the stretch, and I knew Jon was going to be a danger today in terms of the Race to Dubai.
"Tommy... I'm pleased for him. He's battled hard all year and put a good week in South Africa and had a great couple of comeback rounds this week to fight back and deserve it. He's been leading all year and it's good for him to finish it off."
Rahm, who is expected to move to No4 when the new world rankings are released on Monday, did most of his scoring over the last 45 holes, in which he was 18-under par.
The 23-year-old Spaniard said: "I think more than proving to anybody else, it's proving to myself that I belong here. I think that was more important.
"I can't tell you what happened on the first 27 holes. It's not like I played bad. It's just I felt like every mistake I made, every bad shot, led to a bogey which is going to be costly here."
Complete fourth-round scores in the $8 million DP World Tour Championship on Sunday at the par-72 Earth course of Jumeirah Golf Estates:
269 - Jon Rahm (ESP) 69-68-65-67
270 - Shane Lowry (IRE) 69-70-68-63, Kiradech Aphibarnrat (THA) 69-67-67-67
271 - Sergio Garcia (ESP) 70-69-67-65, Dean Burmester (RSA) 70-68-65-68, Dylan Frittelli (RSA) 71-68-63-69, Justin Rose (ENG) 66-70-65-70
272 - Julian Suri (USA) 68-68-68-68, Tyrrell Hatton (ENG) 72-63-69-68,
273 - Patrick Reed (USA) 65-72-68-68, Peter Uihlein (USA) 71-68-65-69,
274 - Matthew Fitzpatrick (ENG) 67-67-72-68
275 - Victor Dubuisson (FRA) 75-67-68-65, Matthieu Pavon (FRA) 71-70-67-67, Li Haotong (PRC) 72-69-67-67, Mike Lorenzo-Vera (FRA) 70-72-65-68,
276 - Francesco Molinari (ITA) 69-71-68-68, Martin Kaymer (GER) 68-72-67-69, Ross Fisher (ENG) 71-68-68-69, Alexander Bjork (SWE) 67-71-67-71,
277 - Haydn Porteus (RSA) 70-70-69-68, Rafa Cabrera Bello (ESP) 73-69-66-69, Tommy Fleetwood (ENG) 73-65-65-74,
278 - David Lipsky (USA) 70-72-64-72,
279 - Jordan Smith (ENG) 75-67-71-66, Callum Shinkwin (ENG) 72-69-66-72, Paul Dunne (IRE) 67-70-67-75,
280 - Wang Jeunghun (KOR) 71-70-70-69, Ryan Fox (NZL) 67-71-73-69, Charl Schwartzel (RSA) 70-72-67-71,
281 - Paul Waring (ENG) 70-74-70-67, Fabrizio Zanotti (PAR) 67-75-70-69, Branden Grace (RSA) 72-71-68-70, Ian Poulter (ENG) 70-69-70-72, Richard Sterne (RSA) 71-71-66-73,
282 - Andrew Dodt (AUS) 70-77-69-66, Alexander Levy (FRA) 67-76-70-69, David Horsey (ENG) 68-76-68-70, Richie Ramsay (SCO) 72-72-68-70, Thorbjorn Olesen (DEN) 74-68-69-71, Soren Kjeldsen (DEN) 68-69-70-75
283 - David Drysdale (SCO) 73-72-69-69, Adrian Otaegui (ESP) 71-69-70-73
284 - Joost Luiten (NED) 73-70-71-70
285 - Bernd Wiesberger (AUT) 71-76-71-67, Scott Jamieson (SCO) 76-71-66-72, Alex Noren (SWE) 74-69-70-72,
286 - Marc Warren (SCO) 72-76-68-70, Andy Sullivan (ENG) 68-76-69-73, Eddie Pepperell (ENG) 75-70-66-75, Scott Hend (AUS) 66-71-71-78,
287 - Graeme Storm (ENG) 76-74-66-71, Lee Westwood (ENG) 75-73-68-71,
288 - Hideto Tanihara (JPN) 73-77-67-71,
292 - Nicolas Colsaerts (BEL) 68-76-72-76, Pablo Larrazabal (ESP) 69-70-74-79,
293 - Chris Wood (ENG) 70-74-70-79
294 - George Coetzee (RSA) 70-76-75-73, Thomas Pieters (BEL) 74-74-72-74, Lucas Bjerregaard (DEN) 75-74-68-77