"That extra hour was a huge bonus,'' said Mallon, who birdied three of her last four holes. "I bet it warmed up 15 degrees (F) from the time when I got here to when I could tee off. Fifty degrees as opposed to 35 is a huge difference.''
Ochoa, already the player of the year, has won seven times this season and earned a record $3,337,993 (2,276,000). Last year at Magnolia Grove, the Mexican star had weekend rounds of 63 and 65 for a 10-stroke victory and 21-under 267 total, both tournament records.
"I'm a little behind now, but I'll try to play good tomorrow and get back to a good position on the weekend,'' Ochoa said.
Sorenstam, sidelined for nearly two months this season by neck and back injuries, is winless since September 2006.
"I thought I played well today,'' Sorenstam said. "I had a lot of good shots, had a lot of opportunities. I don't think I scored as well. I felt really good about my game. I hit a lot of fairways a lot of greens and just had a lot of opportunities.''
Gulbis is making her first appearance in the event after winning the Evian Masters.