World No.1 Inbee Park fired a five-under par 65 on Friday to grab a share of the second-round lead at the LPGA Canadian Women's Open.
South Korea's Park, who has won three major titles this season, was joined on eight-under 132 by US veteran Cristie Kerr, who carded a 66.
First-round co-leader Angela Stanford carded a 68 that left her tied for third on 133 with France's Karine Icher, who posted a 66.
Lydia Ko, whose victory in this tournament last year at the age of 15 made her the youngest player to win an LPGA title, had shared the overnight lead with Stanford.
The 16-year-old phenomenon from New Zealand carded a second-round 69 that left her tied for fifth on six-under 134, alongside England's Laura Davies (66) and American Paula Creamer (68).
Katherine Hull-Kirk (71) was the only Australian to make the cut. She sits 10 shots off the pace.
Seven-time major winner Karrie Webb, Sarah Jane Smith and Lindsey Wright all missed the cut.
Park got off to a hot start at the Royal Mayfair Golf Club course with birdies at the first and second. She holed out from a bunker at the par-four first.
"I always love to start with a birdie," Park said. "It's like a good luck charm for me. I almost never finish a round over par when I start with a birdie."
Park needed just 25 putts on Friday. Her seven birdies included three in a row at the 14th, 15th and 16th.
Park played with Kerr in the first two rounds and said they fed off each other's birdies.
"I think it's always good when you're playing with a partner while she's making a lot of birdies and it makes you want to have more birdies," Park said. "It already felt like a final round, and trying to make more birdies and trying to get the momentum going."
Kerr, who had six birdies and two bogeys, agreed.
"It's always fun to play with In-Bee," said Kerr, who is happy with her own game despite a disappointing bogey at 18.
"I'm mad at myself for knocking my last tee shot, but I did so much good stuff in the last couple days," she said.
