Defending champion Na Yeon Choi shot a 4-under 67 on Friday to maintain the lead after two rounds of the Sime Darby LPGA Malaysia.
Choi sits at 10-under for the tournament and holds a two-stroke lead over Sydnee Michaels, who fired a 65 on Friday to move into second place.
Suzann Petterson followed an opening-round 71 with a tournament-record 64 on the second day to move into a tie for third. Mika Miyazato, Lizette Salas and Momoko Ueda join Petterson at 7-under.
"My game has been feeling right there, but I haven't been able to fire on all cylinders at the same time," said Pettersen, who is seeking her first LPGA win of the year. "Today was nice to get a low round, back in the tournament, two more rounds to go."
Karrie Webb shot a 71 on Friday to slide from second to seventh place. The 37-time LPGA Tour victor is tied with Paula Creamer, Catriona Matthew, Lindsey Wright and Sun Young Yoo at 6-under 136.
World No. 1 Yani Tseng, who finished one stroke behind Choi at this event in 2011, resides near the bottom of the leaderboard after recording rounds of 78 and 72.
Top American and World No. 2 Stacy Lewis carded five birdies, a bogey and a double-bogey during a second-round 69 to sit a 3-under -- good for a 19th- place tie.
Tseng and Lewis are the only players with three tour wins in 2012.
Third-ranked Jiyai Shin, who is attempting to win her third consecutive event, is tied for 27th at 1-under after shooting 70 on Friday. The South Korean captured the Women's British Open and the Kingsmill Championship in her previous two tour appearances.
Michelle Wie is tied for 55th with rounds of 75 and 72 thus far.
Choi, who won the U.S. Women's Open for her first major title in July, started strong on Friday with four birdies on her first nine holes before settling for a pair of bogeys on her back nine.
The South Korea native is attempting to become just the second player on the tour this season to successfully defend her title from a year ago.
"I think I had a pretty good round today," said Choi. "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."
NOTES: Choi is seeking her second tour win of the year ... Tseng is the only other player to successfully defend her title this year. She captured her second straight win at the Honda LPGA Thailand in February ... The top 10 players in the world are in the field.