HOUSTON (FIELD LEVEL MEDIA REUTERS) - A hole-in-one helped Amy Olson grab the first-round lead in the US Women's Open in Houston.

The 28-year-old shot a four-under 67 on Thursday (Dec 10) at Champions Golf Club's Cypress Creek Course for a one-shot lead over Japan's Hinako Shibuno, Thailand's Moriya Jutanugarn and South Korea's Kim A Lim. Jutanugarn and Kim played on Champions Golf Club's Jackrabbit Course while Shibuno toured the Cypress Creek Course.

"That hole-in-one was kind of the highlight of the round," said Olson, a North Dakota native. "I was pretty excited to do that at the US Open."

Seven players are tied for fifth at two under: England's Charley Hull, American Gerina Piller, Thailand's Patty Tavatanakit, Sweden's Linnea Strom, who played Jackrabbit; and Germany's Sophia Popov, the Philippines' Yuka Saso and 21-year-old Swedish amateur Linn Grant, who played Cypress Creek.

Because of concerns about reduced daylight, two courses are being used for the first two rounds. The final two rounds will be contested only on Cypress Creek. Both layouts are par 71.

Olson, who began on the back nine at Cypress Creek, aced the 16th hole with a 139-yard shot. The ball bounced a couple of times and rolled into the cup. She reacted with expected excitement on the tee box.

Olson kept the momentum by notching birdies on two of her next three holes.

She took the lead with a birdie on the par-three eighth hole.

Olson, who has never won an LPGA event, played college golf for North Dakota State, far from the hotbed of collegiate programmes.

Only 23 of the 156 players in the field finished under par on Thursday.

"Obviously, US Women's Open golf courses are tough to learn one, but trying to learn two tough courses is definitely a big task for everyone this week,"said South Korea's Park In-bee, a seven-time Major champion who shot even par at Jackrabbit.

"But with the sunlight (limited), we kind of have to do it."

Kim opened with three birdies on her first five holes while playing the back nine, but she followed with consecutive bogeys at Nos. 15 and 16. She had two birdies and no bogeys on the front nine.

"The start went well," Kim said. "I was able to get a good pace on it and get the balls closer to the green so finish well."

Jutanugarn closed a bogey-free round with eight consecutive pars. Shibuno logged four birdies and a single bogey.

Shibuno said" "Tomorrow the weather is supposed to be bad, so that's why I... have to persevere, so I have to be tenacious. I have to play tenacious, patient golf tomorrow."

Defending champion Lee Jeong-eun of South Korea shot 73, putting her in a tie for 55th place. Countrywoman Ko Jin-young, No. 1 in the Rolex Rankings, also carded 73, with both playing Cypress Creek.

Second-ranked Kim Sei-young, who won her first Major title in October at the Women's PGA Championship, fired a 72 at Jackrabbit.

Another Korean Sung Yu-jin also had a hole-in-one, acing No. 4. However, she managed only a five-over 76 in her tournament debut, with five bogeys, a double bogey and no birdies.

This marked the seventh year in a row that at least one golfer had an ace in the US Women's Open.

The event was postponed from June because of the coronavirus pandemic. A US$1 million (S$1.33 million) payday goes to the winner.

The day before the tournament began, American Andrea Lee withdrew because of a positive coronavirus test. Japan's Ayaka Watanabe took her spot in the field, and she shot six-over 77 at Cypress Creek.

Spectators are not permitted on the course grounds as part of safety protocols. The four-day event concludes on Sunday.