Sorenstam, a three-time winner at this season-ending event, stands at 3-under-par 213 for a one-shot lead over Marisa Baena and Liselotte Neumann.
The conditions -- not to mention a difficult layout at Donald Trump's course -- led to just eight rounds under par on Saturday.
'I think it's been very, very difficult,' said Sorenstam, who is now two rounds removed from her confrontation with Paula Creamer on Thursday. 'This course is difficult with no wind, and to play with gusty winds like we had today is extremely hard.'
Baena didn't seem to mind so much. She matched Cristie Kerr's 6-under 66 from Friday's round for the best score of the week so far.
Neumann reached minus-2 another way. After being tied with Sorenstam for two holes late in her round, she found water at the par-3 17th and finished with a double bogey after taking a drop.
'I played so well today, and unfortunately I put probably one of my worst swings on that ball,' said Neumann, who ended with a 71.
First-round leader Hee-Won Han played with Sorenstam in the final group and matched her 2-over 74. She shares fourth place at minus-1 with Catriona Matthew, who fired a 2-under 70 Saturday.
All in all, 12 women in this 30-player field are within five strokes of the lead. But they are all looking up at Sorenstam, who will be tough to beat as she plays for her 10th win of the season and 66th of her career on Sunday.
Still, she isn't ready to endorse that check just yet.
'It's not just any players,' Sorenstam warned. 'They're great players, and I think they're all hungry to win tomorrow.'
Sorenstam carded a 70 on Friday without a birdie, mixing in two eagles with two bogeys on the front nine before finishing a rare round with nine straight pars.
On Saturday, she bookended her round with bogeys at Nos. 1 and 18. In between, Sorenstam carded two more bogeys to go along with birdies at the ninth and 10th holes.
Her birdies came on putts of 4 and 20 feet -- the second giving her a brief two-shot lead -- but overall Sorenstam's putting was off. After laying up at the par-4 18th, she just missed a par putt from the middle of the green.
Sorenstam also missed a 4 -foot par putt at 13 that dropped her into a tie for the lead with Neumann.
'I just have to make some putts (in the final round),' she said. 'Today I didn't make anything. I think that was the biggest difference today compared with the other two days.'
More consistent was the round of Heather Bowie, who finished with 13 consecutive pars for a 71. She shares sixth place at even-par with Soo-Yun Kang (70) and Michele Redman (74).
Creamer, the Rookie of the Year who argued with Sorenstam over a drop on Thursday, is part of a group tied one stroke further back in ninth place. She shot a 74 in her third round.