Sung Kang earned his first PGA Tour victory with a final-round 67 at the AT&T Byron Nelson in Dallas.
The 31-year-old, who matched the Trinity Forest course record with a 61 in the second round, had to complete 27 holes on the last day after a severe weather delay hit round three.
He entered the final round with a three-shot lead over Matt Every but a sluggish start saw him even par through the first seven holes before birdies through holes eight to 10 got him back on track.
The hot play continued across the back nine when a 23ft birdie on the par-four 15th – the second of three straight birdies – gave Kang the outright lead.
The South Korean closed out 23 under for the tournament, two shots ahead of Americans Every and Scott Piercy, who ended the tournament completely bogey-free.
In a press conference after the tournament, Kang said the win felt “amazing”.
Asked about a telephone conversation with his father in South Korea, where he was heard to say “I did it”, he added: My dad gave me a lot of support when I was young and sent me over to the US when I was 15 and gave me a lot of opportunity to learn from good pros.
“It helped me a lot, giving me support.”
Speaking of his closest challengers, he added: “These guys are unbelievable. Scott Piercy and Matt, making so many birdies on the front. I was like OK, I’m not even going to care about this anymore. Whatever they do, they do. I was just working on my game.”
Masters runner-up Brooks Koepka, who is looking to defend his US PGA Championship later this week, finished fourth at 20 under, while Scotland’s Martin Laird ended in a tie for 35th at 10 under.