World number 60 Li Haotong held off four-time major winner Rory McIlroy to win the Dubai Desert Classic.
The Northern Irishman turned a shot deficit at the start of play into a two-shot lead at the 10th, but his Chinese rival hit birdies on 13 and 15.
An errant McIlroy drive led to a bogey on the 16th.
And although he birdied the final two holes, Li, 22, did the same to win by a shot on 23 under as both players finished with three-under-par 69s.
Li, who won the 2016 China Open and finished third at last year’s Open Championship, is the first Asian winner of the event, and earned the biggest victory of his fledgling career with a tournament record score.
He will also become the first man from China to break into the world’s top 50, having previously made headlines in June 2017 when he threw his putter in a lake at the French Open, only for it to be fished out by his mother.
“Over the last four holes I hit some of the best shots of my life,” Li said. “I just didn’t realise I could make that putt on 15. That was huge. I think that was the turning point.”
McIlroy frustrated after ‘mental errors’
McIlroy has now finished third and second in his two starts since calling an early end to an injury-plagued and winless 2017 campaign, but will rue his wayward drive on the 16th among an otherwise fine display from the tee.
The 28-year-old finished on 22 under par, two shots ahead of England’s Tyrrell Hatton, who saved par on the 18th in a closing 66 despite finding the water with his approach.
A frustrated McIlroy said: “It was a couple of bad shots, a couple of poor decisions, a couple of mental errors, a few tentative putts out there as well.
“I kept leaving myself in places where I couldn’t really give it a run at the hole because they were downhill, downgrain, downwind.
“If someone had told me at the start of the year you’d finish third and second your first two events, I’d say, yeah, I’d take that. But being in the positions I’ve been in and having two close calls it’s a little difficult.
“The competitor in me is very disappointed right now.”