Justin Thomas added another title to his collection after overcoming Marc Leishman following a second play-off hole inaugural The CJ Cup at Nine Bridges on Sunday.
Thomas has enjoyed a breakout year, winning the FedEx Cup and his maiden major at the U.S. Open as he earned PGA Tour Player of the Year honours.
And the red-hot 24-year-old continued his fine form in Jeju after getting the better of Australia's Leishman in a tense climax.
Thomas - who shared the overnight lead with Scott Brown - finished nine under through 72 holes following an even-par 72 in South Korea.
The American star moved clear of Brown but he had company atop the leaderboard in the form of BMW Championship winner Leishman, who like Thomas birdied his final hole at the 18th to force a play-off.
Leishman ran into some early trouble on the first play-off hole but he recovered to almost secure victory, though both players posted pars as the shoot-out continued.
Another recovery was not forthcoming from Leishman, who found the water on the second extra hole and finished with a bogey, paving the way for Thomas to clinch a seventh PGA Tour title courtesy of a birdie.
Leishman's compatriot Cameron Smith ended the tournament one stroke off the pace after shooting a two-under-par 70.
Kim Whee (72) was two shots further back at six under, one ahead of Pat Perez (68), Jamie Lovemark (71), Brian Harman (71), Luke List (72), Brown (76) and Anirban Lahiri (74).
Former world number one Jason Day finished four under following his final-round 71, while Rookie of the Year Xander Schauffele (76) struggled to 17 over the card.