(CNN) -- Cristie Kerr -- seeking her second U.S. Women's Open title in three years -- fired a one-over-par 72 on Saturday to double her lead after the third round in Bethlehem, Pennsylvania.
Kerr leads the field after 54 holes as she looks to add the 2009 U.S. Women's Open to her victory in 2007.
Kerr lies on a two-under total of 211 after 54 holes -- two strokes clear of Korean Eun Hee Ji second on 213, with Taiwan's Teresa Lu and American Jean Reynolds a further stroke adrift.
American Kerr, a 12-time winner on the LPGA Tour, bogeyed the par-four second but answered with a birdie on the par-three fourth.
She took a bogey at the par-three ninth but played the back nine even, following a birdie on the par-four 15th and a bogey on the par-four 16th.
Ji and Lu each fired one-under-par 70s to stay in touch while Reynolds had a 74 after fading with three bogeys in her final four holes.
Meanwhile, American Paula Creamer, who was second overnight, tumbled out of contention with an eight-over-par 79.
Taiwan's Candie Kung and Koreans Hee Young Park and In-Kyung Kim are five adrift on 216, one stroke ahead of Korean Kyeong Bae, Norway's Suzann Pettersen and American Brittany Lincicome.
Elsewhere, Darron Stiles has taken a three-stroke lead in the John Deere Classic at the Deere Run course in Illinois.
Stiles carded a six-under-par 65 to lie on 129 (-13), three strokes clear of Steve Stricker, who tied the course record with a 10-under-par 61 -- highlighted by an eagle on the 17th.