Si Woo Kim birdied the final hole to claim a commanding five-shot victory and a maiden PGA Tour title at the Wyndham Championship.
The 21-year-old, who came close to carding a 59 round on Friday on his way to taking the midway lead, followed a third-round 64 with a three-under 67 on Sunday to finish five clear of nearest challenger Luke Donald.
"I knew I could play aggressively because I had already made the top 125," said Kim. "I felt confident. I didn't have any fear attacking the pin."
Taking a four-shot lead into the final round, Kim saw his advantage increase to six when he tapped in for an opening-hole birdie and Rafa Cabrera Bello dropped a shot at the par-five next.
Brandt Snedeker briefly cut Kim's lead back to four when he followed a birdie-two at the third with a hat-trick of gains from the fifth, only for the Korean to extend his lead by picking up shots at the sixth, eighth and ninth.
As the rain and wind strengthened, Kim carded a first blemish of the day with a close-range two-putt at the 10th and gave the chasing pack hope with successive dropped shots from the 13th.
Jim Furyk moved with three shots by holing a nine-footer at the 14th, but carded his only blemish of the day with a three-putt bogey at the next.
A birdie-four at the long 15th saw Donald claim outright second, as Kim picked up a shot at the same hole to get back four ahead before the threat of lightning saw play halted.
When play resumed 81 minutes later, Kim parred the 17th before rattling in a 15-footer at the last to complete an emphatic victory.
Donald two-putted from distance at the last to card a three-under 67 post his best finish of the season, with Snedker and Hideki Matstuyama tied a further stroke adrift.
Two late bogeys saw Cabrera Bello card an up-and-down 70 and join Graeme McDowell in a five-way way tie for fifth, as Furyk double-bogeyed the last to end eight strokes back.