Thitikul carved out a tense final-round four-under-par 68 to edge out Japan's gallant runner-up Chizzy Iwai by a shot at the Siam Country Club's Old Course on Sunday.
With her non-travelling mother making the short trip to Pattaya to watch her daughter for the only time all season, Thitikul collected herself after missing the green at the last hole to eke out a nerve-wracking, tournament-winning par.
Celebrating her 23rd birthday this week, Thitikul was swiftly showered with water by her peers on the 18th green as she choked back tears during a warm embrace with her overjoyed mum.
"It means a lot," the champion said after taking out the only LPGA Tour event held in her homeland.
"My mum just came up to me when I finished 18 and she cried a lot.
"And then I told her, 'I finally won the tournament in front of you. Like you were here with me'.
"So she's just really emotional. Make me emotional, too."
After starting the day one stroke behind, Iwai quickly turned the championship into a two-way match play-style shootout after collecting two birdies and two eagles in her first 10 holes.
But the 23-year-old was unable to birdie the par-5 18th to force a play-off, her final-round 66 incredibly consigning Awai to the same fate as her twin sister endured last year.
In 2025, Akie Iwai finished runner-up in Pattaya by a single shot to American Angel Yin.
Hannah Green started the day five shots back but Australia's only realistic Sunday contender was unable to make any headway until after falling some nine shots adrift of the frontrunners.
Still, the former major winner would have been heartened to have eagled the par-4 15th and make birdie at No.17 in a final-round 68.
Contesting her first event of the year, Green finished outright seventh at 19 under in an encouraging outing ahead of next week's HSBC Women's World Championship in Singapore, where she won two years ago.
This Sunday's spoils seemed destined to belong to Thitikul - but the Thai superstar did it the hard way..
With a sloppy bogey on the fourth hole, only her third for the week, the home favourite found herself level pegging early with Iwai.
After regaining a one-shot lead with her fifth birdie of the day on the 10th, Thitikul again relinquished her advantage by bogeying the par-4 13th.
But with birdies hard to come by for the leading duo down the stretch, Thitikul found a precious one on the penultimate hole to restore her one-stroke buffer.
She then hung tough at the last to secure the $US270,000 winner's cheque for her third victory in five starts.
Thitikul also boasts two runner-up finishes from her past seven outings and has not finished outside the top seven anywhere in the past seven months.
