Sam Horsfield made a crucial birdie at the 17th hole in the Hero Open at Forest of Arden as he held his nerve to capture his maiden European Tour title.
The Englishman took advantage of a short missed putt by Thomas Detry at the 18th to edge out the Belgian by one shot.
Horsfield safely negotiated the par-three 18th in par himself to finish with a two-under 68 for a total of 18-under 270.
The 23-year-old had earlier seen most of his rivals fall by the wayside on the back nine, as only Detry emerged from the pack with a 66, and it was three shots further back to Sweden's Alexander Bjork, Englishman Chris Paisley and Welshman Oliver Farr in joint-third on 14 under.
World No 224 Horsfield, who was mentored by Ian Poulter at Woburn, began the day with a one-shot lead after seeing a six-shot advantage crumble on the back nine on Saturday, but he quickly stated his intentions with a birdie on the first hole and added three more gains on the front nine, with only one bogey at the fifth.
His forward momentum was stalled by a bogey at the 10th in the third round but this time he rolled in a confidence-boosting long birdie putt at the same hole as his playing partner Rasmus Hojgaard dropped off the pace with a bogey.
Detry, meanwhile, was making stealthy progress up the leaderboard with four birdies in seven holes from the seventh.
The Belgian, who was also chasing a first European Tour win, then holed from 15 feet for another birdie at the 16th and he was suddenly in the lead when he birdied the par-five 17th as Horsfield bogeyed the par-three 15th following a poor greenside chip.
But, just as he had the victory in his sights, Detry pushed his three-foot par putt right of the hole on the 18th to drop back alongside Horsfield on 17 under.
Horsfield made the most of his chance as he smashed a fairway wood over the water to the back of the 17th green from 238 yards and safely got down in two for his birdie.
A cautious tee shot at the 18th left him 50 feet from the pin but he confidently two-putted to secure a memorable victory.
"It's crazy. I can't [describe my emotions]," Horsfield told Sky Sports. "On 17 we wanted to leave a good number and I hit a great shot there."
Farr was firmly in the hunt after an eagle at the seventh but a double-bogey at the 11th and a bogey at the 16th left him with a one-under 71 but a tie for third still gave him his best European Tour finish.
Paisley closed with a 70, while Bjork, who bogeyed the 15th and 18th, carded a 69.
Denmark's Hojgaard, 19, was two over on the back nine after a double-bogey at the 16th and a bogey at 18, his level-par 72 leaving him in a four-way tie for sixth on 13 under.
German Maximilian Kieffer (68), Matthieu Pavon of France (70), who holed a 75-foot putt for birdie at the 15th, and Finland's Mikko Korhonen (72) were alongside Hojgaard.
Miguel Angel Jimenez ended his record-breaking 707th European Tour appearance with a level-par 72 for a share of 34th place.