EVIAN-LES-BAINS, France -- South Koreans In Gee Chun and Sung Hyun Park each birdied eight holes to card a 63 for a share of the first-round lead at the Evian Championship on Thursday.
In the fifth and final major of the season, New Zealander Lydia Ko's bid to defend her title -- and clinch a third career major by the age of 19 -- got off to a rocky start as she finished seven shots behind the co-leaders.
"It was tricky for me because on the back nine I was not hitting fairways," said Ko, who has 14 career wins on the LPGA Tour and finished second in this event as a 16-year-old amateur in 2013. "Hopefully I'll be able to hit some fairways tomorrow."
Chun, the 2015 U.S. Women's Open champion, said she felt nervous after missing the cut here last year, but she hardly let it show.
"I could see the putting lines and I was good rolling the ball on those lines," she said. "The greens are getting softer this year."
While Ko's play was patchy, with a bogey and only two birdies, Ariya Jutanugarn of Thailand had a day to forget with a 2-over 73 featuring a triple-bogey.
Ko and Ariya have a good chance at Evian of taking the Annika Major Award, which rewards the golfer with the best combined record at all five majors of the season.
American Annie Park, who joined the tour this year, posted an eagle and five birdies in a 7-under round of 64 to move into a tie for third place with Olympic bronze medalist Shanshan Feng, who was third here last year. They are one stroke behind the leaders.
"That was fun. It was good to have my mum back on the bag," Annie Park said. "The last time she caddied was Hawaii in April. She keeps things light and does some dances out there."
Ranked 201st, Annie Park enjoyed a run of birdie-birdie-eagle on her front nine, then starting and finishing with birdies on the back nine.
American Angela Stanford posted a 6-under 65 to move into fifth, one shot ahead of South Koreans So Yeon Ryu and Eun-Hee Ji.
Starting in muggy afternoon conditions, Ko played in a group with South Korean Hyo Joo Kim, the 2014 champion, and Norway's Suzann Pettersen, the 2013 winner.
Ko birdied the fifth hole, bogeyed the eighth hole and saved par on No. 10 after her tee shot landed in the rough between two trees.
"It's a good thing my wood shots and chip shots were good enough," said Ko, who last year became the youngest man or woman to be ranked No. 1.
Women's PGA champion Brooke Henderson of Canada ended the day one shot ahead of Ko at 2-under.
Pettersen had a difficult day, joining Ariya and American Lexi Thompson, last year's runner-up, at 2 over.
U.S. Open winner Brittany Lang had a nightmarish round, carding two double-bogeys and three bogeys for a 5-over 76.