"I knew that she had a pretty good round today," Pak said. "It's pretty surprising because the weather out there was really hard. You don't think anybody is going to go really low. But she did. So it must mean she had a really hot putter."
At the same time that Pak was missing a short birdie putt at 17, Pressel dropped in another birdie putt at the 18th to draw within a shot.
Pak then hit two 3 woods just short of the green on the closing par-5 hole, chipped to 4 feet and stroked the birdie putt in the heart of the cup.
In-Kyung Kim, who said she idolized Pak while growing up in South Korea, was the first to challenge Pak. Kim birdied the first seven holes to get to 9 under and two shots off the lead before Pak had even teed off.
"That was my first time to birdie seven holes in a row, so that was pretty cool," she said. "I kept making birdies. I thought maybe I could shoot 57 today! I made seven birdies in a row, like, what's going on?"
But she cooled off, suffering a costly bogey at the 12th when she drove into the right rough. She finished with a 65 and was alone in third at 205.
Alena Sharp, who had a first-round 65 only to shoot a 74 on Friday, bounced back with a 67 and was fourth at 206.
Another shot back were 1988 Farr champ Laura Davies (67), Laura Diaz (68), Carri Wood (70), Linda Wessberg (66) and 2004 Farr winner Meg Mallon (70).
Pak said she'll play the course, and not against Pressel.
"I don't think I have to do anything just play like I've been playing the last three days," she said. "My game is solid enough to just play comfortably. I'm trying to not make too many mistakes and play one shot at a time."