Lydia Ko is on course to make LPGA history after shooting an even-par 72 for a one-stroke lead in the CN Canadian Women's Open.

The 15-year-old South Korea-born player, now competing under the New Zealand flag, was looking good for a two-shot lead heading into Sunday's final round but a bogey five on the 18th hole saw her drop back to eight-under.

Ko, who headed into the tournament on the back of the US Women's Amateur victory two weeks ago, will become the youngest winner in LPGA Tour history if she hangs on.

"I don't think I was more nervous than other days," she said. "I tried to have more fun, but my score wasn't as good. I mean, 72 is better than 73 or any other score, so I'm pretty happy.

"It's good to stay at the top of the leaderboard, but my first goal was to make the cut and hopefully top 15 or something. To be up there is just an honour, especially playing against the world's best."

Ko, who will be 15 years, four months and three days old tomorrow, knows some of the world's best players will be ready to pounce on Sunday as the number two ranked Stacy Lewis and South Korean trio Jiyai Shin, Chella Choi and Inbee Park are just one shot adrift with Sydnee Michaels and Moira Dunn from America tied for sixth at five-under.

Choi shared the lead with the New Zealand over the weekend while Lewis shot a 66 to shoot up the leaderboard.

"Stacy Lewis is second in the world just trailing behind Yani (Tseng). I played with Stacy and I know she's a great player," Ko said.

"It's quite nerve-racking, but I'm really here for experience and fun, and I'm having fun at the moment. If I don't win tomorrow, I don't think I'll be disappointed. If I do win, I'll take it like an honour.

"It's kind of a thrill to see lots of people and especially them trailing behind.

"Fifteen-year-olds don't lead at an LPGA event all the time. I'm very surprised. But I've been playing really good golf and I've been really confident with my game.

"I'm just going to try my best. I've got to play my own game. I can't concentrate on what the other players are doing. If they shoot 66 and I shoot 68 and I lose, I can't control what they do. So I'm just going to play my game and have one shot at a time."

Lexi Thompson holds the record for the youngest LPGA winner as she was 16 when she won the Navistar Classic last September.

Golf 365