The 25-year-old closed with a gritty one-under 70 to finish at seven under, two shots clear of compatriot Poom Saksansin in a tense final-round duel.

The win earns Sadom a place in The Open at Royal Portrush in July and propels him to the top of the Asian Tour Order of Merit, leapfrogging Mexico's Carlos Ortiz and American Ollie Schniederjans.

“Yeah, honestly, I'm very excited, of course. I tried to concentrate more than last three rounds, so I could do it. I'm very happy,” Sadom said. “It is a big honour to win this event – it’s one of the biggest in the region.”

Poom, who held the 54-hole lead, carded a 73 to settle for second. Korea’s Songgyu Yoo (72) finished third, four shots behind Sadom. Hong Kong’s Taichi Kho fired the week’s lowest round, a sparkling 64, to share fourth with seven others, including Zimbabwe’s Scott Vincent and 19-year-old Korean amateur Minsu Kim.

Sadom last triumphed at the Singapore Open in 2022, adding to his 2019 Bangabandhu Cup title. He has since recorded three runner-up finishes and five other top fives.

It was a rollercoaster final round. Sadom began the day one back, dropped a shot on the first, then watched Poom double the second. The pair traded leads throughout until Sadom edged ahead for good with a birdie on 12 and back-to-back bogeys from Poom on 14 and 15.

“I'm happy when I play with my Thai friends, it helps, and Poom is a great player. His putter and the short game is fantastic. So, yeah, very happy to play with him today,” Sadom said.

“I have changed my swing a little bit, I was trying to find a way to get better. So now I think I have, and I can rely on it.”

Sadom becomes the third Thai to lift the Korea Open trophy, following Thongchai Jaidee (2000) and Jazz Janewattananond (2019).

The victory also secures his second start in a Major, having tied for 11th at The Open at St Andrews in 2022 — the best-ever finish by a Thai golfer at a Major.

Poom, despite the narrow loss, impressed with his precision iron play and deft short game on a layout that favoured length off the tee.

“It was a tough day, not too bad actually to finish in second place and keep my card. But I got some bad news from my house, so the result is not important now,” he said, after learning post-round of his grandmother’s passing.

The Asian Tour resumes at the International Series Morocco from 3–6 July at Royal Golf Dar Es Salam.