Tom Lewis claimed his first European Tour victory since 2011 by winning the Portugal Masters by three shots.
The Englishman, who trailed Lucas Herbert by two shots overnight, shot a five-under-par 66 to finish 22 under in Vilamoura.
Australia’s Herbert had to settle for a share of second with Eddie Pepperell after a double bogey on the final hole.
Sergio Garcia finished tied for seventh and Thorbjorn Olesen tied 20th before playing in next week’s Ryder Cup.
“It is unbelievable. I am so happy. It has been a rough ride,” Lewis told Sky Sports after securing a two-year exemption on the European Tour.
The world number 184, 27, won his sole European Tour title at the 2011 Portugal Masters and was the leading amateur at that year’s Open at Royal St George’s but has been in form recently on the second-tier Challenge Tour.
Lewis overturned Herbert’s two-shot overnight advantage by posting four birdies on the front nine at Dom Pedro Victoria Golf Course.
He briefly lost his one-shot lead after a bogey at the 10th before responding a hole later with a fifth birdie of the day.
Lewis looked in trouble after finding water off the tee at the par-five 17th, but made a superb par putt of 30 feet to maintain his slender advantage.
Herbert then hit his final drive into the water, taking the pressure off Lewis who was able to comfortably par the 18th.
Australia’s Herbert eventually signed for a 71 to miss out on a first professional win.
England’s Pepperell threatened the leaders but had to settle for a sixth top 10 of the season after a 67.
Spain’s Garcia, who will make his ninth Ryder Cup appearance in France, carded a 65.
Denmark’s Olesen finished with a 67 going into his Ryder Cup debut.
“I feel a lot better after this round. I had two weeks off, I had a week without golf, so all and all it has been a good week,” said Olesen.