The 28-year-old past champion, who took home her second major championship at the US Open in 2022, moved up to five under after matching the week's best score at Lancaster Country Club in Pennsylvania.
While Andrea Lee scored five birdies and two bogeys in her 67 to put herself in contention for her first major championship on Sunday, overnight leader Wichanee, who has never placed in the top 10 at a major, was able to keep up her pace and card a 69.
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