Frenchman Julien Quesne matched the Aloha course record with an eight-under-par 64 to win his maiden title at the Andalucia Open on Sunday.
The 31-year-old, ranked 322 in the world, stormed through to pass the overnight leader Eduardo De La Riva and finish with a total of 271 for 17 under par.
Teenage Italian Matteo Manassero was two strokes behind him in second after a round of 68, while Spaniard De La Riva carded a 70 to finish third, three strokes off the pace.
"It's the best day of my life," Quesne said on the European Tour's website (www.europeantour.com).
Quesne, who had never previously finished higher than 16th in a European Tour event, birdied four of the last five holes, and after a magnificent approach to the 18th showed great composure to hole a five-foot putt.
"I knew that if I holed the putt at the last I'd have a good chance," added Quesne, who graduated from last season's Challenge Tour.
"I'm very happy. It's very quick for me to win this year."
Manassero and De La Riva were both 15 under at that stage, but neither could force a play-off over the closing holes.
England's David Lynn failed to build on a 30-foot eagle at the fifth as he finished fourth, one ahead of South African Hennie Otto and Quesne's compatriot Raphael Jacquelin, who had led for much of the afternoon.
Tournament host and local favourite Miguel Angel Jimenez, who at the age of 48 had been aiming to become the oldest winner on the European Tour, finished in a share of seventh after a final round 71.