Lorena Ochoa and Cristie Kerr both posted rounds of four-under 68 Thursday to share the first-round lead at the HSBC Women's Champions.
Ochoa and Kerr were joined atop the leaderboard by Hee Young Park and Angela Stanford.
Last week's winner Ai Miyazato carded a three-under 69. She shares fifth place with Sophie Gustafson, Christina Kim and Song-Hee Kim.
Ochoa had a steady start to her round with a birdie and six pars over her first seven holes on the Garden Course at Tanah Merah Country Club.
The women's world No. 1 converted back-to-back chances from the eighth to turn in three-under. Ochoa joined Park in the lead with a birdie on the 11th, but trouble loomed.
Ochoa, the 2008 champion, stumbled to bogeys on 12 and 14 to fall two back. However, she fought back into a share of the lead with birdies on 16 and 17.
Kerr got off to a rough start with bogeys on the first and third. She headed to the back nine at plus-one thanks to a birdie on the par-four seventh.
After five consecutive pars, Kerr caught fire. Starting at the par-five 13th, she poured in four straight birdie chances to get within one of the lead. Kerr birdied the last to share the first-round lead.
Park was the first one in the clubhouse at minus-four. She birdied the third and fourth, but from the eighth to the 13th, Park didn't make a par.
The 22-year-old bogeyed the eighth, but birdied nine and 10 to move to three- under. Park dropped another stroke on the 11, came right back with a birdie on 12, then bogeyed the par-five 13th to drop back to minus-two.
Park righted the ship with a birdie on the 16th. She finished with a birdie at the last to get in at four-under.
Stanford is the only one of the leaders that was bogey-free. She had two birdies on both nines. On the front nine, her birdies were on seven and nine. On the back nine, Stanford birdied the 13th and 16th to gain a piece of the lead.
NOTES: Juli Inkster, Karrie Webb and Suzann Pettersen are among six players tied for ninth at two-under 70...Defending champion Jiyai Shin is at minus- one, while Michelle Wie bogeyed the last two holes to shoot even-par 72, which left her tied for 19th...Natalie Gulbis withdrew after carding a one-over 73 Thursday.