Pak was at 3-under 141, one shot ahead of Inbee Park, Paula Creamer, Mika Miyazato, and Sandra Gal. Park shot 70, Gal had 71, and Creamer and Miyazato shot 72.
Defending champion Yani Tseng followed her opening 76 with a 75 to finish the two rounds at 7-over 151, and was positioned to barely make the cut in a tournament she dominated a year ago.
First-round leaders Beatriz Recari, Giulia Sergas and Ryann O’Toole, fell off the pace on a day that a swirling wind added yet another challenge on the narrow Locust Hill Country Club course. Sergas and O’Toole shot 76, and Recari had 78.
Cristie Kerr, the runaway winner in 2010, was 2 under after 76.
Slumping Michelle Wie missed the cut with rounds of 74 and 82.
CHAMPIONS TOUR: In Birmingham, Ala., Bill Glasson shot a 3-under 69 on to take a two-stroke lead over Russ Cochran after the second round of the Regions Tradition, the second Champions Tour major of the year.
Glasson had a 9-under 135 total at Shoal Creek, and has made only one bogey– Friday on No. 16 – in the first 36 holes. He is seeking his first victory since winning the 1997 Las Vegas Invitational.
Cochran had a 68. Defending champion Tom Lehman was three strokes back along with Fred Funk, Brad Bryant and Jeff Sluman.
EUROPEAN TOUR: In Bro, Lee Westwood shot 4-under 68 to maintain a three-stroke lead after the third round of the European Tour’s Nordea Masters.
The third-ranked Westwood had a 16-under total. He won the tournament in 1996 and 2000.
Ross Fisher was second after 65.
Former Augusta State golfer Jamie Elson shot 75 and is in 75th place at 218.
NATIONWIDE TOUR: In Leon, Mexico, Tag Ridings shot 3-under-par 69 to take a one shot win in the Mexico Open.
Ridings is at 9-under 135 at El Bosque Golf Club.
Lee Williams (67), Ryan Armour (72) and Paul Haley II (71) are tied for second at 136.
Aiken’s Matt Hendrix shot 70 and is tied for seventh at 138.
CURTIS CUP: In Nairn, Scotland, Amy Anderson teamed to win two matches to help the United States take a 4-2 lead over Britain and Ireland after the first day.
Anderson and Tiffany Lua beat Holly Clyburn and Bronte Law 2 and 1 in the morning foursomes, and Anderson and Emily Tubert topped Pam Pretswell and Charley Hull 4 and 3 in the afternoon fourballs.