Defending champion Na-yeon Choi of South Korea shot a four-under 67 to take a two-stroke lead at the halfway stage of the Sime Darby LPGA Malaysia on Friday.
The U.S. Women's Open winner in July for her first major title and only victory of the year, Choi was 11 under after birdies on Nos. 12 and 13. The South Korean bogeyed the par-3 17th and closed with a par at Kuala Lumpur Golf and Country Club.
''I think I had a pretty good round,'' Choi said. ''I got two bogeys, but I think I'm still in pretty good position. I really like to play this golf course. I have a lot of confidence. I hit a lot of good shots with my irons. I really looked forward to this week, to get good results like last year.''
American Sydnee Michaels was second after a 65. The U.S. LPGA Tour rookie had five birdies on the back nine in hot and humid conditions.
''I definitely got on a roll,'' Michaels said. ''I gave myself good birdie chances every time. I made the putts. So I was rolling the ball really well. ... It is really, really hot. But, I mean, I have my little sun umbrella, my compression sleeve, so I'm trying to manage.''
Norway's Suzann Pettersen shot a tournament-record 64 to match American Lizette Salas and Japan's Momoko Ueda and Mika Miyazato at 7 under.
''Yesterday felt like I just had to flush through a round of golf after a long week in Africa last week,'' Pettersen said. ''I've been feeling really good with my putter, starting in Alabama a couple, three weeks ago. It's just continuing. I feel like I can be aggressive, trust my instinct.''
The eight-time U.S. LPGA Tour champion is winless this year.
''This year has been kind of a little bit of an odd year,'' Pettersen said.
Salas had a hole-in-one on the par-3 15th in her 67. She used a 9-iron on the 130-yard hole.
''I'll take it,'' Salas said. ''It's only my third hole-in-one, first on tour. You don't get to hear that all too often, a hole-in-one in Malaysia. So that's pretty cool. I'm just having fun.''
Ueda also shot 67, and Miyazato had a 69.
Australia's Karrie Webb, tied with Choi for the first-round lead after a 65, had a 71 to drop into a tie for seventh at 6 under. American Paula Creamer also was in the group at 6 under after a 67.
Min Lee, the 17-year-old Taiwanese amateur who opened with a 66, was disqualified for signing an incorrect scorecard after shooting a 73. She signed for a 4 on the par-4 13th, but made a 5. Lee also was disqualified last month for signing an incorrect scorecard after the Taiwan Amateur Championship, costing her a victory.
Michelle Wie was 5 over after a 72.
Top-ranked Yani Tseng followed her opening 78 with a 72, leaving her tied for 61st at 8 over among the 69 remaining players. The Taiwanese star has struggled after winning three times in the first five events of the season.