In Gee Chun of South Korea took advantage of early-afternoon conditions during the KPMG Women's PGA Championship on Thursday at Congressional Country Club, matching a tournament record with an 8-under-par 64 at Bethesda, Md., to finish atop the field after one round of action.

"I'm trying to make the focus on the course for the process, not the result," Chun said. "I'm trying to enjoy to play golf more on the course, more talk with my caddie. I'm happy with the good round today."

Chun is five strokes ahead of Thailand's Pornanong Phatlum and South Korea's Hye-Jin Choi, who are tied for second after shooting 3-under-par 69s. Jennifer Chang and Paula Reto of South Africa are tied for fourth at 2 under.

A group of nine tied for sixth place at 1 under includes defending champion Nelly Korda, Jennifer Kupcho, Hannah Green of Australia, Nasa Hataoka and Ayaka Furue of Japan, Brooke Henderson of Canada and three South Koreans: A Lim Kim, Sei Young Kim and In Kyung Kim.

Sei Young Kim was the 2020 Women's PGA Championship winner, while Green won in 2019 and Henderson won in 2016.

"I think once I got to the ... third or fourth hole, I was OK," Green said. "Even par is a great score out here today."

Chun had a relatively modest start to her round at 1 under through five holes whole starting on the back nine. She got on a roll starting at the par-4 15th hole with four consecutive birdies to make the turn at 5-under 31.

A three-time winner on the LPGA Tour and U.S. Women's Open champion in 2015, Chun had her only stumble of the day on the par-4 10th hole with a bogey. She then fired four more birdies over the next six holes to take a commanding first-round lead.

Fifteen players ended the opening day at even par, including Inbee Park of South Korea. The seven-time major winner finished on top of the Women's PGA Championship in 2013, 2014 and 2015.

The purse for this week's third major of the season doubled to $9 million, with 99 of the top 100 players on the LPGA Tour money list competing. The winner's share also doubled to $1.35 million.

The purse was just $2.25 million in 2014, the year before the PGA of America began its collaboration with KPMG.