SINGAPORE -- Spain's
Munoz played in the day's first group and finished with seven birdies. Five players at Sentosa Golf Club shared second at 67: Stacy Lewis, Karin Sjodin, Lizette Salas, Pornanong Phatlum and Sun Young Yoo.
Munoz is coming off her strongest season on tour, winning her first title at the Sybase Match Play Championship and enjoying nine top-10 finishes.
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"I don't know what it is but my best three rounds on tour have been first tee time," she said. "I really like it. You don't have to wait, it's super nice, the greens are perfect. I think it gets me going."
Paula Creamer was in a four-way tie at 68 despite an injured right shoulder from a car accident. The five-car accident happened on the way to the airport after the Honda LPGA tournament in Thailand.
Also at 68 were top-ranked
Tseng, a five-time major winner, was five shots off the lead before sinking a 25-foot putt for eagle on the 18th hole. Tseng hasn't won a tournament in nearly a year, but she has started the 2013 season with a second-place finish at the Australian Open and a tie for third at Thailand last weekend.
She said she made a bet with her manager, Naya Hsu, on Thursday morning to better motivate herself. If she scored a 68 or better, Hsu agreed to go skydiving with her in Hawaii.
"When that putt dropped in, I was so happy," Tseng said. "I was looking for her. I saw her face, I think she's going to cry.
"I think it feels good because I haven't had that feeling for a long time," she said. "The last two weeks, kind of a little rushed, trying to play well on the first day. And today I've been patient because I know it's only the first day, I still have three days left."
Creamer was just happy to be on the course after her accident. She said she jammed her shoulder when she hit the dashboard of the car and suffered whiplash after slamming her head off the headrest.
"At the beginning of the round, I really couldn't feel my right side and I didn't know if I was going to be able to even go," she said. "I thought if I could get through the first five holes, I would be OK. I have no expectations whatsoever this week," she said.
Second-ranked Na Yeon Choi, who is trying to close in on Tseng's No. 1 ranking, shot a 69. Michelle Wie, South Korea's Jiyai Shin and Australia's Karrie Webb were at 71, with Pettersen at 73. Defending champion Angela Stanford had a quadruple bogey on the par-4 13th en route to a 76.