Mindy Kim maintained her two-stroke lead in the LPGA State Farm Classic, following her opening career-low 64 with a 5-under 67 on Friday to reach 13 under.
Kim had seven birdies -- four in a row on Nos. 12-15 -- and two bogeys at Panther Creek Country Club.
Top-ranked Yani Tseng (66) and Shanshan Feng (65) were tied for second.
Kim, winless in two seasons on the LPGA Tour, said she has struggled with focus after bad holes, but thinks she's maturing and managing herself better on the course. The American proved it Friday, quickly rebounding from a bogey on the par-4 10th -- her opening hole of the round.
"I would just get angry. I mean if I made a stupid bogey, which, on No. 10, it really was," Kim said. "Honestly, in the past I just didn't practice in my offseason. I would just hang out with my friends, and I think I did a little too much of that. This offseason, I cut out a lot of time for golf. I spent a lot of time on the golf course preparing myself mentally with my new coach.
"If I make bogey, I can't go back and make par, right? Just have to get over it."
Tseng won the season-opening LPGA Thailand for her sixth tour title in four years.
"I had eight birdies and two bogeys that I don't think I should make," Tseng said. "I feel like I lost a little focus. But I had a great round. I'm very happy."
Feng closed strong, birdieing Nos. 15, 16 and 17.
"I think this course really fits me," said Feng, who led last year after the first round. "I've had two top-5s here before. I feel really comfortable hitting on the course."
Tseng played the first two rounds with Kim.
"She really pushes me hard to play better," Tseng said. "She would get close and I want to get close,too. I don't want to hit it out of range if she's close. It's very nice to have a player like that to compete with in the same group."
Jiyai Shin aced the par-3 second hole en route to a 68 to reach 10 under. She made a 50-footer for birdie on No. 2 on Thursday, then had the hole-in-one on the 146-yard hole.
"It's my favorite hole," Shin said. "I can't wait for tomorrow."
She used an 8-iron.
"I couldn't see the hole, but the reaction of the gallery, they were screaming," said Shin, who has eight lifetime aces. "Watching the ball flight, I thought it might get close."
Amanda Blumenhurst (67) was 9 under, and Brittany Lincicome, coming off a victory Sunday in New Jersey, had a 69 to join Paula Creamer (68) and Jennifer Johnson (67) at 8 under.
Defending champion Cristie Kerr (67) topped a large group at 7 under. Michelle Wie was eight strokes back at 5 under, following an opening 72 with a 67.
Experts on the business and game of golf. The best coaching tips and latest golf news delivered straight to you. Sign Up to get the latest.