The 22-year-old phenomenon, who became the first Thai golfer to win a major at the 2016 British Open, began the day tied for the lead with South Korea's Amy Yang and ended it a stroke clear of Australian Minjee Lee, who clung on tenaciously after also firing a 66.
"It means a lot to me. I said this week to my caddie I want to win once on a links course and I did it and it is a dream come true," Ariya told LPGA.com.
Ariya will head to next week's British Open at Royal Lytham & St Annes with a significant boost to her confidence, but she warned that her victory on a links course did not make her a racing certainty to be a title contender.
"Still tough for me and I will have to be patient," she said.
"I have a pretty good feeling so hope next week to play my A game."
Ariya's victory -- her third this year -- will see her go top of the world rankings for a second time in her career on Monday, having spent two weeks in top spot in June 2017.
"It means a lot to me to be number one but last time it didn't help me thinking about it too hard, so I am just going to work on my game."
Yang, one of a plethora of Korean golfers in the mix, never got going and dropped away to finish tied for fifth on seven-under after a 73 to put a dampener on the weekend of her 29th birthday.
American Tiffany Joh, who set the pace for the first two rounds before failing to cope at all with the gusting wind while shooting 80 on Saturday, rebounded slightly to finish tied for eighth on five-under having carded a 70.