Ahn set scoring marks all weekend. Her opening round 65 tied the old course record. She then set the 36-hole record (8-under 136) by five strokes and her tournament total of 204 shattered the mark of 213 set by Se Ri Pak in the inaugural event last year.
'I am so happy,' said Ahn, who pocketed $187,500 for the victory. 'I wasn't obsessed with winning the tournament, and I think that helped me win.'
Gloria Park put a major scare into Ahn as she fired a course-record, 10-under 62 on Sunday. She vaulted into a tie for second, from a share of 26th. She was joined in second place at 9-under-par 207 by Laura Davies, Grace Park and Pak, the 2002 champion.
Ahn, who led wire-to-wire, got off to a fast start Sunday with a birdie on the first at Nine Bridges Golf Club. She climbed to 10-under with a birdie at the par-5 third.
The 19-year-old found trouble at the fourth. She bogeyed the hole, but responded with a birdie on No. 8. Around the turn, Ahn moved to 11-under with a birdie at the par-4 10th.
Ahn dropped another stroke at the 13th, but her lead was still two. She responded with a birdie at the very next hole to extend her lead.
After Gloria Park finished at minus-9, things got interesting as Ahn bogeyed the 16th to see her lead fall to one. Showing veteran-like poise, the Japan LPGA Tour rookie eagled the 54th and final hole to win by three strokes.
Thanks to this win, Ahn can now concentrate most of her time on the LPGA Tour.
'If I get to the United States, I will try to produce good results,' she said.
Gloria Park began the day at 1-over par but started with a birdie at the first. She started to make her move up the leaderboard with back-to-back birdies from the seventh.
Gloria Park again converted back-to-back birdies from the 10th to get to 4-under. The Seoul native then sank three consecutive birdies from the 13th before closing with birdies on Nos. 17 and 18.
'I made some confident putting today, and the weather was good,' said Gloria Park.
Pak made an early run with two straight birdies from the first, but a bogey at the par-4 fourth ended her momentum. She managed an eagle at the par-5 ninth and a birdie at the last to climb back into a share of second place.
'I am a bit disappointed, but it was a real meaningful game,' said Pak, the second-ranked woman in the sport. 'I think Ahn is a really good player.'
Davies picked up birdies at the first and third, but stumbled to a bogey at the fourth. She later birdied Nos. 7 and 9. Around the turn, the 40-year-old dropped another stroke with a bogey at the 10th.
She responded with birdies on 14 and 16. Davies faltered to her third bogey of the day at the 17th, but closed with a birdie at the last to share second.
Grace Park wrapped birdies at the first and third around a bogey at the second. She ran off eight straight pars before a birdie at the 12th. Park moved to 3-under for the round with a birdie at the 14th and closed with a birdie at No. 18 for the third straight round.
Suzann Pettersen and Jung Yeon Lee shared sixth place at 7-under-par 209. Soo-Yun Kang and Rachel Teske tied for eighth at minus-6, while Lorie Kane was one stroke further back at 5-under-par 211.
Michelle Wie mounted a rally in the final round, but could not overcome her opening-round 85 as she finished in last place. She closed with a 2-under 70 to end the event at 17-over-par 233.