Starting the day six shots behind and well ahead of the final group, Mun made his move on the back nine with six birdies – including four in a row from the 11th – to finish 10-under, three shots clear of Thailand’s Jazz Janewattananond and Koreans Baekjun Kim and Junghwan Lee.

He posted his score two hours before the final group finished and waited nervously to see if it would hold. Jazz missed good birdie chances on 14 and 15 and bogeyed the last. Canada’s Yonggu Shin also threatened but collapsed with a 10 on the 18th, ending in a tie for 12th.

Mun’s charge began with four straight birdies, putting him just one behind Jazz. He caught him with another birdie on 16, then pulled ahead with a superb approach to six feet on the tough 18th, setting up one of just three birdies there all day.

“I couldn't be happier to be on top of the leaderboard in a tournament I've always wanted to win,” said Mun, who plays out of Namseoul.

“When the birdie putt on 18 went in, I thought I could at least make it to play-off. I talked to my caddie about making sure I made that birdie, and I'm happy that I did.

“The last three holes at Namseoul Country Club are particularly tricky. I focused on playing steady and making par rather than being aggressive. I wasn't aiming for birdies, just putting the ball in the right position.”

It’s his first Asian Tour win and fourth on the Korean PGA Tour. His last win in Korea was in 2022. The 33-year-old, who first qualified for the Asian Tour in 2018, has come close before with top-five finishes at the Singapore Open and Shinhan Donghae Open.

His round of 63 was two shots off the course record and showed up Namseoul’s reputation as one of the hardest courses, with its steep hills and fast, sloping greens. Luckily, the sun came out after a week of rain.

Despite Mun’s brilliant round, Malaysia’s Danny Chia still holds the record for biggest final-round comeback on the Asian Tour – seven shots – at the 2002 Taiwan Open, played during a typhoon.

Jazz, who started the day tied for the lead with Kim, was aiming to become the first overseas winner in 21 years but faded on the back nine.

“Oh, I mean, it was so hard out there today, it was a grind fest. I mean, I tried to grind as much as I could. I didn't give up at all at any point. But it was just hard, you know, like I didn't have my best stuff out there, but overall, I think I finished up well.

“Congrats to Doyeob. I don't know how he shot eight under par today, but if it wasn't for him, I would be doing a play-off with another player right now. So overall, good.”

Zimbabwe’s Scott Vincent, also in the mix early, faded badly with a 75 to also tie for 12th.