Japan's Kazuki Higa finished with back-to-back birdies as he shot a flawless final round six-under 65 on Sunday to win the Asian Tour's Shinhan Donghae Open by two strokes.
Higa's 20-under 264 total gave him a two-stroke victory over third-round leader Tirawat Kaewsiribandit of Thailand, whose one-over 72 dropped him into a three-way tie for second with Cho Min-gyu of South Korea and Canada's Yonggu Shin on 18-under.
It was the in-form Higa's third win of the season after two victories on the Japan Tour.
The 27-year-old said patience had been key during a final round of five birdies and no dropped shots.
"There were a lot of pars along the way, especially on the back nine," said Higa. "But I just believed in myself and knew that I could do it."
The tournament was being held in Japan for the first time in its long history, having been previously played in South Korea every year since 1981.
Higa plays on the Japan Golf Tour but the victory at Koma Country Club near Osaka now gives him multi-year exemptions also on the Asian and Korea tours.
"I know I have opportunities to play on the Asian and Korea Tours now which is exciting for me. It will open more doors to other opportunities as well," he said.
Tirawat had opened up a three-shot lead after the third round and looked as though he might run away with it after carding a rare albatross two at the par-five third hole to move to 21-under par.
But Tirawat struggled for consistency and his rollercoaster final round also included two birdies, a double bogey and four bogeys, the most costly of which came at the final hole.
Needing a birdie to force a playoff with clubhouse leader Higa, Tirawat attempted to drive the green at the short par-four 18th but instead found rough left of the putting surface.
He chipped up to 10 feet but disastrously three-putted for a bogey five to hand Higa the trophy.