The Swede is going for her ninth LPGA Tour win of the season, and must win in California to keep alive her hopes of setting a single-season win record.

Sorenstam made up a two-stroke deficit on the final hole, countering Kerr's bogey with a birdie to finish four under for the round.

That leaves both players 15 under for the tournament with Sunday's final round to go.

Sorenstam has set some lofty goals for herself this season, and says the quality of the field would make the win even more special to her.

"It's the 20 best players in the world - the very best you can find," she said.

"A win here would certainly boost your confidence. In my case, that would be nine wins, which puts me right where I want to be."

Victory for Sorenstam would leave her needing to claim the final five events of the season to set a single-season win record.

Cristie Kerr, who shot a course-record 64 on Friday, had another rollercoaster round, totaling six birdies and three bogeys - all on the back nine.

Rosie Jones is in third place with a three-round total of 204, a stroke ahead of Se Ri Pak and first-round leader Michele Redman.