Japan's Ai Miyazato has set her sights on reclaiming her No. 1 status.
She shot a 6-under 66 on Friday for the first-round lead at the Safeway Classic at Pumpkin Ridge Golf Club west of Portland.
Miyazato had a one-stroke lead on Teresa Lu of Taiwan and Jee Young Lee of South Korea.
Miyazato is in a five-way battle for the world's top ranking. American Cristie Kerr is currently No. 1, followed by Miyazato, Jiyai Shin of South Korea, Suzann Pettersen of Norway and Yani Tseng of Taiwan.
"It's really fun, really exciting because the top five players all represent different countries, so it's really a good motivator for me," Miyazato said.
In a changing of the guard since the retirement of Lorena Ochoa earlier this year, Miyazato, Kerr and Shin have traded the top ranking six times in the past three months.
"Even though it was just for two weeks, I was so very happy," Miyazato said about her time on top. "I was happy because I experienced something that I never really experienced before, and so it will just be really good for my future as my career goes on."
Miyazato has won four times on the LPGA Tour this season.
Also making a case is the 21-year-old Tseng, who won the Women's British Open on Aug. 1 for her second major victory of the season and third in three years. The Kraft Nabisco Championship winner in April, Tseng made a 6-foot par putt on the final hole at Royal Birkdale for a one-stroke victory over Katherine Hull. She also won the 2008 LPGA Championship. But Tseng shot a 3-over 75 at the Safeway.
South Korea's Chella Choi, Taiwan's Amy Hung, Japan's Momoko Ueda and American Brittany Lincicome were two strokes off the lead with 4-under 68s. Veteran Juli Inkster joined a large group at 3 under.
M.J. Hur is the defending champion of the tournament nestled in farmland at the base of the Cascade Range about a 20-minute drive west of Portland. She won her first-ever title by beating Pettersen with a birdie on the second playoff hole.
Hur shot a 74 on Friday on the 6,546-yard Ghost Creek Course. It is the tournament's second year on the rural course after 19 years at Columbia Edgewater County Club.
The top-ranked Kerr, who won the event in 2008 at Columbia Egdewater, shot a 70. Michelle Wie, looking for her second victory after taking last year's Lorena Ochoa Invitational, was at even par going into Saturday's second round.
Fan favorite Natalie Gulbis had to withdraw because of ongoing back trouble.