South Korea's Kim Jae-hee marked her 23rd birthday spectacularly by securing her maiden KLPGA Tour victory in her 91st start at the Hana Financial Group Singapore Women's Open on Sunday.

Kim closed with a flawless six-under-par 66 at Tanah Merah Country Club's Tampines Course to secure a one-shot win over compatriot Bang Shin-sil, whom she had started the day in joint second place with.

Kim carded six birdies to finish at 17-under-par 271 for the tournament and narrowly edged out Bang, who carded a 67.

Penultimate stage leader Oh Soo-min suffered heartbreak after squandering a three-shot lead and settled for outright third place with a 71, finishing with a 273 total.

This dashed the hopes of 15-year-old Oh, who had aimed to become the first amateur to win on the KLPGA Tour since Choi Hye-jin in 2017, as well as the fourth youngest winner of all time in the prestigious circuit.

"This is my first victory, and I feel it's a little bit belated because from much early on I wanted to win a tournament," said Kim, who pocketed a cool S$198,000 winner's cheque for her feat.

"But I'm very happy to begin this season with this victory under my belt. I feel very comfortable, relaxed and at the same time I feel very proud.

"This is actually the first time I played on my birthday. So, when I heard about the tournament dates, I just thought, oh, I'll be playing on my birthday!

"But to win this tournament I think makes it much more special and I understand I'm the third player to win during a tournament. I will remember this day for a long time to come."

With a three-shot deficit to overcome, Kim rose to the occasion, recording a hat-trick of birdies from the fourth hole and adding another on the ninth to tie for the lead with Oh at 15-under at the midway point.

Despite bogeying two of her opening three holes, Oh staged an incredible fightback, responding with three birdies to stay at the top.

Kim's consecutive birdies on the 13th and 14th holes helped her pull two shots clear of the chasing pack and proved to be the decisive moment of the day.

Although both Bang and Oh attempted to apply pressure in the closing stretch, Kim remained steady, warding off any potential bogeys to seal the deal.

Kim acknowledged that several near misses in the past had equipped her with the experience needed to secure the breakthrough she had been longing for.

"Definitely those second places have actually helped me. I think when you have a lot of experience playing in the leaders’ group, you feel less nervous," said Kim, who had six runner-up finishes in her career before today's victory.

"Having been in contention on the final day on many occasions, you actually feel you're edging much closer to a victory."

For Bang, she wasn't disheartened despite missing out on the third title by a whisker.

"It was really hot but I did my best physically. My energy level was low so it was hard to keep up (in the later rounds)," said Bang.

"I knew that it was very close, but I didn’t feel too nervous, I just did my best when it came to every shot. Second place was a very good start for me and I would like to play consistently for the rest of the season."

Oh can certainly hold her head high after delivering a remarkably impressive performance, surpassing her previous best of a tied-ninth finish at the 9th Kyochon 1991 Ladies Open last year.

If anything, her performance boosted her confidence and fuelled her desire to participate in as many KLPGA Tour tournaments on a regular basis, aiming to secure as many top-five finishes as possible.

"When I decided to enter this tournament, I thought ‘let’s just make the cut, win the best amateur award and be in the top five’ – those were my initial goals," said Oh.

"I was a little bit sorry to not win but there’s so much that I learnt through this competition that compensates for not being able to win."

Malaysian professional Ashley Lau carded a final round of one-under-par 71 to finish in T27 on five-under-par 283. Lau who began her Sunday with a par streak up until the 12th hole, made three birdies and two bogeys in her last six holes to wrap up her week in Singapore. 

Only entering her second year of turning professional and soon to be returning to playing full-time on the Epson Tour, Lau will be taking this week in stride.

"A lot of positives this week, I was driving it really good this week. The only thing I would say was that putting, I was somehow struggling to read the greens. Usually putting is my strong suit, but this week it was a let down for sure," Lau shared.

She was paired with runner-up Bang Shin-sil on the the first two rounds of the tournament and found Bang's gameplay to be a good motivator and inspiration to follow. 

"I think the first two days I got paired up with (Bang) Shin-sil, she was playing really good and it was fun for me to watch her game and learn a lot of things from her as well."

When asked about what she would be taking away from the week, Lau mentioned that her performance in Singapore will be giving her the insights she needs to improve her game.

"It's nice to be competing again after my two weeks break and just playing alongside strong field gave me a little bit of insight of what I have to work on."