Michelle Wie secured a share of the first-round lead in the Lorena Ochoa Invitational after carding a six-under 66.
Wie, who won the tournament in 2009, tops the leaderboard along with Angela Stanford and Candie Kung.
The American birdied the first two holes at Guadalajara Country Club and began the back nine with four birdies in a row.
Second-ranked Stacy Lewis was a stroke further back along with Inbee Park, Cristie Kerr, So Yeon Ryu and Karine Icher.
Lewis holds a 58-point lead over Park with two events to go in the player of the year points race, leaving her well-placed to become the first American to claim the accolade since Beth Daniel in 1994.
Mexico's Ochoa, who won 27 LPGA Tour titles before retiring at age 28 in 2010, missed last year's event before the birth of son Pedro in December.