Sorenstam is the defending champion, and Ochoa won last week's Corona Morelia Championship in her native Mexico.
"I think the fairways are quite generous," Sorenstam said. "When it's this windy anything can happen. I must say that the greens today are very, very fast."
"You have to be prepared," said Ochoa. "You just got to being patient and not stress or be worried and just keep it going."
16-year-old Michelle Wie continued her yearlong struggles by shooting 2-over 74 to tie for 12th place.