"I just didn't play that well coming in," Wie said. "I didn't play as well as I wanted. I think I know exactly what I need to work on. I'm going to work hard the next two weeks and try to win."
Shin will play Sun Young Yoo — a 2-and-1 winner over fourth-seeded Yani Tseng — in the semifinals Sunday morning. In the other quarterfinals, 10th-seeded Angela Stanford beat Catriona Matthew 5 and 3, and No. 30 Amy Yang edged Haeji Kang 1-up.
"This match was so big," Shin said. "When I saw the pairing, I was a little bit worried because she's so long."
The 22-year-old Shin is chasing her first LPGA Tour title of the year after winning six times in the last two seasons. She also has 23 international victories.
The South Korean star, at 5-foot-1 nearly a foot shorter than Wie, took the lead for the first time when Wie bogeyed the par-4 15th after hooking her drive into the tall rough. Shin then won the par-3 16th, holing a 15-foot birdie putt. Wie hit her tee shot into the deep right bunker, blasted out to 18 feet and missed her par try.
"I just didn't hit good shots," Wie said. "Sometimes that happens."
The match ended when Wie pulled her 10-foot birdie putt well left on 17.
"She's a superstar," Shin said. "I just tried to focus on my game."
In the morning third-round matches, Shin beat Beatriz Recari 4 and 3, and Wie overcame shaky ballstriking to top Karine Icher 3 and 2.
In the afternoon, Wie birdied the par-5 second to take a 1-up lead, and Shin squared the match with a tricky 5-foot par putt on the par-4 seventh.
Wie won the par-3 12th with a 25-foot birdie putt from the edge of the green, skipping and punching the air in celebration.
"It was just 12, so I'm not worried because I've got six holes left," Shin said.
Shin pulled even on the par-4 13th with a 12-foot birdie putt after Wie hit a flop shot to a foot following an approach that went off the back of the green.
"I was thinking, this is my birdie chance," Shin said.
Stanford won six of the last eight holes to finish off Matthew in 15 holes, then rushed off to catch the Yankees-Mets game.
"I asked my caddie on 11 what time it was," Stanford said.
She beat former Duke star Amanda Blumenherst in 20 holes in the third round.
Yang beat Kang with a birdie on the par-5 18th.
"I can't wait to play tomorrow," Yang said. "I might be tired when I wake up because I played like 30-something holes."
Yoo finished off Tseng, the Kraft Nabisco winner in April, with a halve on 17.
"I felt really comfortable out there," Yoo said.
DIVOTS: Wie changed outfits during the break, switching from a black ensemble with pants to a light green shirt and white skort. She also wore sunglasses in the afternoon match. ... The losing quarterfinalists earned $37,500 and the third-round losers got $18,750. The winner will receive $375,000 from the $1.5 million purse.
