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Kiwi Lydia Ko got off to a successful start in her title defence at the Canadian Women's Open, firing a five-under par 65 to grab a share of the lead.

The 16-year-old defending champion is tied for the lead after Thursday's first round at Royal Mayfair Golf Club with American Angela Stanford and Cristel Boeljon of The Netherlands.

"It was a pretty special week last year ... so to kind of have that kind of week again this week would be like a double miracle for myself," said Ko, of Auckland, New Zealand.

Paula Creamer and Cristie Kerr carded matching four-under 66s to share fourth, while world No. 1 Park In-Bee, Choi Na-Yeon, Karine Icher and 22-year-old Canadian Jennifer Kirby, who played alongside Ko, all shot three-under 67s.

"I felt very comfortable out there and ended up making a few putts, and good round," said Kirby.

Ko was paired with 17-year old and European Solheim Cup team member Charley Hull (69) and Kirby. She said when everyone in the group is playing well like Thursday it usually translates into more birdies.

"I started off really well with a birdie, but when I have a birdie on the first hole I haven't really played that well," said Ko. "I was kind of nervous that I did make a birdie on the first. I think I played pretty solid today.

"But I think I played good because the whole group seemed to play good and make lots of birdies, so we were in a really good rhythm as a whole group."

Ko became the youngest winner in LPGA history last year at 15 years and four months when she captured the crown in Vancouver. This season, Ko has played in nine prior LPGA events, including four majors.

All but one of the players in last week's Solheim Cup will be playing this week, with Sweden's Caroline Hedwall having entered after becoming the first player to go 5-0 in a Solheim Cup in helping Europe defeat the USA women 18-10. Hedwall opened with a 68 Thursday.

Park finished second to Ko last year, even though she collected a winner's check because Ko was an amateur.

Park seeks her seventh title of the year this week, having won three major titles and leading the LPGA money list with $2.14 million.