Chien hit a five-under par 67 at Carlton Woods to move out in front - one ahead of world number two Nelly Korda of the United States - in the first women’s major of the year.

The 32-year-old bogeyed the opening hole before landing birdies on four of the last six in the front nine, including three in succession.

Two further birdies in the final two holes saw Chien, who finished tied fourth at last week’s LOTTE Championship, top the standings on day one.

"It feels so hard," said Chien.

"We’re doing very well today, just focused on what I want, what we want, and which way we can miss."

Korda is one of six players just one shot behind Chien after producing a four-under par 68 in Texas.

The Tokyo 2020 Olympic gold-medallist hit three bogeys and seven birdies, including two in the last two holes.

"I took advantage of the par fives today," said Korda.

"I think I birdied them all, so that was important, as I’m a bit of a longer hitter.

"Overall I played pretty well.

"It was nice to finish the way I did with just a tap-in birdie, but made a couple mistakes here and there where it was more of the yardage where I was a little too aggressive and I left myself a little short-sided chip, and with the rain that we got during the delay, I wasn’t sure how it was going to react, bump-and-running it or flopping it."

Fellow Americans Lilia Vu and Marina Alex are also on four-under-par along with South Korea’s Chella Choi, Japan’s Ayaka Furue and Australia’s Stephanie Kyriacou.

Angel Yin of the US is alone on three under, while 2018 British Open champion Georgia Hall of England is one of 14 players on two under.

Competition is due to continue tomorrow.