Stacy Lewis fired a 7-under 65 on Saturday to grab a 2-stroke lead after three rounds of the Navistar LPGA Classic.
Lewis, a 2-time winner this year, finished 54 holes at 15-under-par 201.
Angela Stanford carded a 4-under 68 to move into second place at minus-13. Lizette Salas managed a 2-under 70 to finish alone in third place at 12-under- par 204.
Haeji Kang (67) and Mi Jung Hur (72) share fourth place at minus-11.
Defending champion Lexi Thompson, who was the first- and second-round leader, struggled to a 2-over 74. She dropped into a share of sixth place at 10- under-206.
Last year, Thompson, then 16, became the youngest winner in LPGA Tour history.
Lewis flew out of the gate. She birdied the first two holes, before narrowly missing another birdie try at the third. Lewis converted birdie efforts at four and five, both from inside four feet, to move to 12-under, where she shared the lead with Thompson.
"I just went out there and tried to hit good shots and it worked out and I made a few early," Lewis said. "I hit them close on four and five. It was a pretty easy 4-under through five."
The 2011 Kraft Nabisco champion parred three in a row from the sixth at the Senator Course at the Robert Trent Jones Golf Trail.
Lewis dropped her approach shot within three feet at the ninth and knocked that in for her fifth birdie of the opening nine.
Around the turn, Lewis drained a 10-footer for birdie on No. 11 to move three clear of the field. After four pars in a row, Lewis ran home a 20-foot birdie putt to get to 15-under.
Lewis 2-putted for par on the final two holes to end there.
"I think the wind started to pick up and it became a completely different golf course. It was playing tough," Lewis said. "There were some hole locations you just couldn't go at. From there on in, I just made birdies when I could and made pars the rest of the day and it was just really solid."
Stanford opened with a birdie at the first. After stumbling to a bogey on No. 7, she birdied the eighth to make the turn at 10-under.
The 5-time tour winner made a long par-saving putt at the 12th and that spurred her on.
Stanford drained a 9-footer for birdie on No. 14 and made it two in a row as her 20-foot birdie try on the 15th found the bottom of the cup. She birdied the 17th from seven feet out.
"With the wind and some of the pin placements were tricky, and I don't remember the wind blowing from this direction. I think it played a lot tougher today," Stanford said in a televised interview.
Thompson had eight pars and one bogey on the front nine. After her first birdie of the day at the 11th, Thompson pulled her drive left into tall grass. She took an unplayable lie penalty.
She found the green with her third shot from over 200 yards out, but 3-putted for double-bogey. Thompson also bogeyed the 13th, but got that shot back with a birdie on No. 15.
NOTES: Lewis will go for her fourth LPGA Tour title on Sunday ... Lewis has won just one of the previous three events in which she owned a piece of the 54-hole lead ... Stanford earned her fifth tour win earlier this year at the HSBC Women's Champions.