Paul Peterson won his first European Tour event as he held off the challenge of defending champion Thomas Pieters to claim the title at the D+D REAL Czech Masters.
The American came into the final round two shots behind Pieters but followed up his course record 64 on Saturday with a 67 to get to 15 under and beat Pieters by a single shot.
Peterson was playing in just his 23rd European Tour event and becomes the 11th first-time winner this season and just the seventh left-hander to win in Tour history.
"This is the best feeling in the world," he said. "My team and I have put in so much hard work and long hours by everybody and I'm just so happy.
"We had this as a goal this year and to be able to accomplish it means so much.
"It was fantastic, the crowds have been great all week. My sports psychologist was on the bag this week and my coach and my girlfriend came all the way from Phoenix. It's just so great to have all the team here."
Pieters climbed off a 6000-mile flight from Rio de Janeiro after finishing fourth in the Olympic Men's Golf Competition, knowing that back-to-back wins here and at the Made in Denmark could still earn him an automatic qualifying place for the Ryder Cup in September.
That chance has now gone but the Belgian can still be very pleased with his defence after he claimed his maiden win here in Prague 12 months ago.
One man who is virtually assured of his seat on the plane to Hazeltine is Matthew Fitzpatrick, who finished in fifth place at ten under after a 69.
Fellow Englishmen David Howell and Ryan Evans finished one shot ahead of him after rounds of 68.
This is the best feeling in the world. My team and I have put in so much hard work and long hours by everybody and I'm just so happy - Paul Peterson
Both of the leading duo had a birdie and a bogey in their first two holes but a Peterson gain on the third cut the gap to one and he played a stunning approach on the fifth to within a foot to share the lead.
He then took advantage of the par five ninth for the third day in a row to move to 13 under and take a one-shot lead at the turn.
A dropped shot after finding a greenside bunker on the 11th dropped Peterson back into a share with both the leaders taking advantage of the par five next.
Pieters lipped out from five feet on the 14th and left a birdie effort agonisingly short on the next, with Peterson making him pay when he put his tee-shot to two feet on the par three 16th and moved ahead with two to play.
Pieters threw down the gauntlet with an approach to three feet on the last but Peterson rolled in from 17 feet to seal the title with a birdie.
"I didn't really watch him hit a shot today, to be honest," added Peterson. "I know he's a long hitter and I play a little bit more precision golf. I was just trying to frustrate him because I knew I would be hitting in first a lot so I just stuck to my process all day and was able to hit some fantastic shots under the pump."
Evans was bogey-free in his closing 68 while Howell had four birdies and two bogeys before an eagle on the 12th catapulted him up the leaderboard.
Fitzpatrick made gains on the first, fourth, ninth and 12th to get within a shot of the lead but a three-putt bogey on the 15th ended his chances.
American David Lipsky was then at nine under after a 70, a shot clear of English trio Gary Boyd, Robert Rock and Graeme Storm, and Swede Robert Karlsson.