Byeong Hun An defeated fellow South Korean Tom Kim in a play-off to claim the Genesis Championship title on home soil at Jack Nicklaus Golf Club Korea.
The home favourites began the day as joint leaders, but the chasing pack ensured there would be a chaotic final round with six players at the summit in some capacity.
Kim eventually took the initiative down the final stretch as he moved one clear on 17 under after An bogeyed the penultimate hole to slip back.
Both players had birdie putts from eight feet at the last, with An applying the pressure by holing his effort to re-join Kim at the top of the leaderboard.
The world No 25 looked to have followed suit, but his putt lipped out to deny him victory and force a play-off.
Going down the last once again in the play-off, both players tried to reach the par-five hole in two, which left Kim in a precarious position with his ball in the thick rough by the greenside bunker.
He fired his third shot across the green and into the main stand before chipping back onto the putting surface, while An chipped to within three feet to leave a birdie chance.
Kim missed his par putt, leaving An with two chances to claim victory. The world No 36 only needed one to lift the second DP World Tour title of his career, over nine years since his first at the BMW PGA Championship in 2015.
"It's great, I've had a great season, it's been too long [to win] on the main Tour," An said.
"All I tried to do is show some great golf in front of the home fans, it's been a while since I've played in front of them.
"It feels amazing, it's a bit of a shame that Tom had a bit of a mess there, but it's been a great tournament for me, I've really enjoyed it.
"There has been a lot of fans out there supporting me and Tom and I feel like we had a great battle. I just got a little bit lucky to be a winner out there I think."
Ricardo Gouveia, who began the week in 154th place on the Race to Dubai, earned his playing privileges for next season with his first top-20 finish of the campaign.
He was in sole third at 16 under to climb to 100th in the rankings, where the top 114 will retain their card for 2025.
Antoine Rozner was a shot further adrift in fourth and Guido Migliozzi carded the lowest final-round score with a flawless 65 to finish on 14 under in fifth.
