Salas was practically flawless in delivering a 30 on the front nine to go from a one-shot deficit to a two-shot lead.

She then made her first bogey of the week after 45 holes and didn't make another birdie in a third straight 5-under 67.

Korda, the 22-year-old coming off a victory last week on the LPGA Tour, played bogey-free but failed to use her length to capitalise on the par 5s on the back nine of Atlanta Athletic Club and signed for a 68.

They were at 15-under 201, five shots clear of a trio that includes Patty Tavatanakit, the Thai star who won the first LPGA major of the year at the ANA Inspiration.

Tavatanakit ran off four straight birdies toward the end of her round for a 65.

Joining her five shots behind were Giulia Molinaro of Italy (66) and Celine Boutier of France, who had a 69 while playing in the final group with the co-leaders.

Both Salas – whose only LPGA Tour victory came seven years ago – and Korda are seeking their first major and will be in the final twosome.

A day after a sizzling round of 65, Gabriela Ruffels carded an ever-par 72 to be three under and best-placed of the Australian contingent, with Minjee Lee (75), three over and Su Oh (76, four over) well back.

Ruffels had two birdies and two bogeys on Saturday, unable to re-find the magic of her LPGA Tour career low from Friday.

Korda is a rising star, the younger sister of Jessica Korda and the daughter of former Australian Open tennis champion Petr Korda.

She already has five wins and is No.3 in the world, the highest-ranked American and she has the gallery on her side in Georgia.

Salas kept plugging away, determined to stay happy even as the grind of a major deep into the weekend began to take its toll.

Tavatanakit never lost hope even as she fell 10 shots behind at one stage.

"Not going to lie, I like chasing more than I love having the lead," she said.

"I have something to look forward to or just look up to all the time."

- Doug Ferguson, Associated Press