Choi started Sunday one stroke behind Kim Song-hee but used a round with five birdies and two bogeys to pass Kim and collect her fourth LPGA title and $270,000. She had a 54-hole total of 10-under 206.
"I am really happy to defend my title this year," said Choi, who turned 23 Thursday. "There were a lot of expectations from the fans … in order to live up to those expectations, I had to let everything out on the course and concentrate on every shot. That paid off."
Vicky Hurst, who closed with a 2-under 70, was second at 8-under and won $166,643. Kim, who had five bogeys over her final 10 holes, sagged to a 1-over 73 and settled for third place and $120,888.
Choi, Hurst and Kim played together in Sunday's final group. Kim seemed in good position to win her first LPGA title when she opened a 2-stroke lead on Hurst and was three up on Choi.
But Choi had a birdie at the eighth hole and Kim a bogey at No. 9 that allowed Choi to get back within one. Choi had a birdie at 10 while Kim had a bogey and the lead switched hands. Birdies at 11 and 13 increased Choi's advantage.