The 31-year-old did see her lead trimmed by a shot after a second-round 67.

Unsurprisingly, the American was unable to match her stunning first-round 62, a course record, but still hit five birdies for a total of 13-under par.

“I had pretty low expectations for today, to be honest,” Joh told the Tour’s official website on Friday. “I honestly probably would have taken anything under par, but on the first hole right away we made a 45-footer, and I just started laughing.

“I didn’t even know what to say. So yeah, it was a really good start, and I guess I just kept rolling with it.”

Meanwhile, US Open champion Ariya Jutanugarn posted a bogey-free 65 to get within three of the lead.

She was joined on 10 under by South Korea’s Amy Yang who shot 66.

Germany’s Caroline Masson equalled Jutanugarn’s 65 to move into fourth.