According to LPGA projections, either South Korean Ryu So-Yeon or Thailand's Ariya Jutanugarn will take over the top spot come Monday.

The two have been closing in on New Zealand's Ko for weeks, and Ryu is in the driver's seat this week as the only player in the trio teeing it up at the Stockton Seaview Hotel and Golf Club near Atlantic City, New Jersey.

Ryu, currently ranked third in the world, can leapfrog world number two Ariya to seize number one if she finishes third or better -- although a tie for second or third could open the door for Jutanugarn.

If Ryu is fourth or worse, Ariya will rise to number one, the LPGA has projected.

"Since I dreamed about the LPGA tour I also dreamed about becoming the number one player in the world," Ryu said this week as she prepared for Friday's opening round.

"I definitely want to become number one at some point, and I'm working really hard for that as well.

"But I think the more important thing is to enjoy this moment and enjoy playing golf. I believe that will get me to number one."

Ko has held the number one spot for 84 straight weeks and 103 weeks overall.

The 26-year-old Ryu thrust herself into the race for number one with a victory in the year's first major, the ANA Inspiration -- where her playoff victory came after American Lexi Thompson was controversially penalized in the middle of the final round for an infraction on the previous day.