Nicole Broch Larsen and Mo Martin shared the third-round lead, but it was home hope Brooke Henderson's rousing 63 that thrilled fans on Saturday at the LPGA Canadian Pacific Women's Open in Ottawa.
Henderson, the 19-year-old major winner from nearby Smiths Falls, produced a course record round of eight-under to race up the leaderboard, finishing before the overnight leaders even teed off.
"I knew I had to get going," Henderson said. "Today is moving day, and I moved, that's for sure."
A day after she birdied the par-five 18th to make the halfway cut on the number, Henderson notched eight birdies without a bogey and was seven-under for the tournament and three shots off the lead.
Henderson broke the previous Ottawa Hunt & Golf Club course record of 64 set by Taiwan's Tseng Ya-ni in 2008.
"I felt like I could make something happen," Henderson said. "I made putts that I didn't even know I could make, and I made shots that were just great."
Denmark's Larsen, a one-time winner on the Ladies European Tour in her first LPGA season, birdied two of the last three holes for a 66.
"I've made 21 birdies so far, so I know it's scorable," said Larsen, whose caddie this week is five-time LPGA winner Sophie Gustafson.
"It's our first week together," Larsen said. "But she's definitely a help out there. We're just trying to kind of play our game for three holes and then we go three holes and starting a new game. That's kind of kept me in the birdie moment. It's been really good so far."
Martin, the 2014 Women's British Open champion from the United States, birdied the final two holes for a 67 to join Larsen on 203.
"I had another solid front and then a hot back nine, so that's a good combination here," Martin said. "Pretty much just continuing the momentum from the last couple days."
Overnight leader Chun In-Gee of South Korea carded a one-under 70 to lie a stroke off the pace on 204.
Chun, who has four runner-up finishes in 2017 but no wins, bounced back after a double-bogey at the 16th with back-to-back birdies on 17 and 18.
South Korean Lee Mi-Rim posted a 66 for 205, where she was joined by US veteran Cristie Kerr, who carded a 68.
Henderson was among half a dozen players on 206 that also included world number one Ryu So-Yeon of South Korea and China's Feng Shanshan.