The South Korean, chasing her first major victory at the Sahalee Country Club in Washington state, shot a third-round 71.

US golfer Lauren Hartlage carded a 69 to move into second alongside Japan’s Miyu Yamashita with overnight joint leader Sarah Schmelzel a further stroke back after a 74.

Women’s Open champion Lilia Vu carded the best round of the day with a 68 to tie for fifth on three under par — four off the lead — with Lexi Thompson, seeking a major title after announcing her retirement from full-time golf at the end of the season, Caroline Inglis, Jin Young and Hinako Shibuno.

England’s Hull was within two of the lead after three successive birdies at the start of her back nine, but a six on the par-three 17th after finding water off the tee dropped her to a tie for 12th, six shots off the pace.

“My mate goes: ‘What happened to you on 17 yesterday? You nearly hit it in the water’,” said Hull, who has been battling knee injury.

“I got to the tee box and I’m thinking to myself: I never nearly hit in the water. Then I’m thinking about the water and just fatted it into the water. It’s human.

“It wasn’t like me. I played so well out there today and didn’t do one thing wrong and got up and down when I needed to.

“But I’m still positive going into tomorrow’s round. Anything can happen.”

Yang, 34, has carded just three bogeys in 54 holes as she looks to add a major title to her five LPGA Tour wins.

“I grew up watching so many great players in the past, and I saw them winning all the major championships,” she said. “I dreamed about playing out here because of them. I work hard for this.

“It’ll mean a lot, but we have still got 18 more holes out there and that’s a lot of golf left for major championship.”