Choate beat 2006 U.S. Women's Amateur Champion Kimberly Kim, 3 and 2, in the second round, and then defeated defending champion Tiffany Joh, 4 and 3, to reach the quarters at Kearney Hill Golf Links.
'It's pretty remarkable,' the 21-year-old Choate said. 'They're both great players. Tiffany hit a few errant shots on the back nine. It wasn't her day, by any means.'
Stephanie Kono, a 17-year-old from Honolulu, got past Felicia Espericueta, 2 and 1, and then beat Pamela Ontiveros, 2 up.
'I started playing well in the playoff for the last (match play) spot,' Kono said. 'I'm just trying to take it one match at a time. Actually, one hole at a time.'
Choate will face Michelle Shin and Kono will take on Mina Harigae in the quarterfinals Friday. The other matches feature South Korea's Wonjoo Choi facing Ryann O'Toole and Kayla Mortellaro going against Stephany Fleet.
Choate's victories were the most surprising of the day. The Drury University senior made the tournament as an alternate and didn't know she would play until last Tuesday, five days before play began.
'The way she played today, that's the way you should play a match,' Joh said. 'She didn't make a single bogey and she just never opened any doors. She just let me, and probably Kim too, just make all the mistakes. That was probably a textbook match.'
Two-time NCAA Division I player of the year Amanda Blumenherst lost in the second round to 2006 semifinalist Sara Brown, 3 and 2.
The Women's Amateur Public Links is one of 13 national championships conducted by the USGA, 10 of which are strictly for amateurs.
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