American Mo Martin carded a second consecutive 69 to claim the halfway lead in the Ricoh Women's British Open at Royal Birkdale.
The 31-year-old, who has recorded just one top-10 finish in 63 career LPGA starts, fired five birdies and two bogeys to finish on six-under-par, three shots ahead of Spain's Beatriz Recari and Korea's So Yeon Ryu.
Recari carded a superb 67 which featured one bogey and six birdies, three of them coming on the last three holes, while Ryu recovered from a double-bogey on the second with birdies on the fourth, 10th, 11th and 18th to return a 70.
Fellow Korean Sun-Ju Ahn matched Recari's 67 thanks to four birdies in the last five holes to finish two under par alongside Paraguay's Julieta Granada.
England's Georgia Hall is the best-placed home player after adding a 72 to her opening 73 to lie one-over-par alongside defending champion Stacy Lewis, while 50-year-old Laura Davies was two shots further back after a 72.
Scotland's Vikki Laing produced the shot of the day, holing a 5-wood from 240 yards for an albatross on the par-five 17th on her way to a 68, a 10-shot improvement on her opening round.
The halfway cut fell at seven over par and US Open champion Michelle Wie missed out by two shots after a 78.