London, ON (SportsNetwork.com) - So Yeon Ryu fired a course-record tying 9- under 63 on Thursday as she claimed a 1-stroke lead at the Canadian Pacific Women's Open.
Ryu, who has nine top-10 finishes this season, is seeking her third career win on the LPGA Tour. Her last victory came at the 2012 Jamie Farr Owens Toledo Classic.
"I failed (to win) so many times, but at the same time I learned so many things," Ryu said about her season. "I've just got through all the tests, and I want to make it this one."
Na Yeon Choi carded an 8-under 64 during her opening round at London Hunt and Country Club to sit in second place, while Anna Nordqvist is alone in third at 7-under 65.
Inbee Park, who won the LPGA Championship last week for her fifth career major title, Azahara Munoz, Danielle Kang and Xi Yu Lin share fourth at 6-under 66.
Two-time defending champion Lydia Ko shot a 2-under 70 to sit among a large group of players tied for 34th place. Ko is seeking her third straight win at this event.
Ryu opened her bogey-free round with a par before converting a birdie at the second. She would add birdies at the fourth and seventh to make the turn at 3- under.
Ryu poured in four birdies in a five-hole span from the 10th to jump to 7- under.
Another gain at the 17th pulled her even with clubhouse leader Choi, and she made it two straight birdies at the 18th to move into sole possession of the lead.
"When I was warming up, my shot was really bad, so I had zero expectation I could play this low," Ryu said. "But I played really well, so I'm really happy with what I'm doing today."
Choi had earlier started on the back nine and got her round started with a birdie. After rolling in another birdie at the 13th, she picked up another shot at the 16th to make the turn at 3-under.
She then caught fire around the turn, reeling off five straight birdies from the first to race to 8-under. That run included a pair of chip-ins at the first and fifth.
A bogey at the sixth halted her momentum, but she quickly got that shot back with a birdie at the seventh and parred her final two holes to end at minus-8.
"The first hole I started with a birdie. It just feels good, I guess a lot of vibes from there," said Choi. "I didn't really try to shoot a low score, like 7-, 8-under today, but I think that's why I played well today."
Nordqvist posted seven birdies during her opening round to finish in third place.
NOTES: Ryu has 27 top-10 finishes since her last win ... Choi has 10 top-10 finishes since her last win at the 2012 CME Group Titleholders ... Ryu had three chip-in birdies in her opening round ... Karen Sjodin had a hole-in-one at the second hole. It was the seventh of her career, but first on the LPGA Tour.