PRIDDIS, Alberta (AP) -- Ariya Jutanugarn had five birdies in a six-hole stretch and shot an 8-under 64 on Friday to take a three-stroke lead in the Canadian Pacific Women's Open.
A week after withdrawing from the Rio Olympics because of a left knee injury, the 20-year-old Thai star played 20 holes Friday at Priddis Greens. She bogeyed the par-5 18th for a 68 in the completion of the delayed first round, then made eight birdies in her bogey-free second round.
"I just had to rest and take care of my knee," Jutanugarn said. "After that, I feel like just play golf. It didn't feel like anything changed."
South Korea's In Gee Chun and Northern Ireland's Stephanie Meadow were tied for second. Chun closed birdie-eagle for a 67. Meadow had a 69. The former Alabama player had a seven-hole stretch without a par, making three straight birdies, three straight bogeys and a par.
"It's a rough little stretch there in the middle, and I just kind of had to pull myself together." Meadow said. "I definitely saved myself on the back nine with my short game. It wasn't pretty, but I got it done, and that's what golf's about."
Three-time champion Lydia Ko was four strokes back, and Canadian star Brooke Henderson was eight behind.
"I played pretty solid the last few days," Ko said. "Hoped for a few more putts to drop, but it's just really tough out there with some pins being tucked and on little slopes. ... There's still a lot of golf to be played."
In the event before the Olympics, Jutanugarn won the Women's British Open for her fourth victory of the year. She won three straight tournaments in May, and shares the tour victory lead with the top-ranked Ko with four.
The second-ranked Jutanugarn began the second round with birdies on Nos. 1 and 2, ran off four straight on Nos. 17-2 and added birdies on Nos. 4 and 8 to get to 12 under. Hammering 2-iron and 3-wood off the tee, Jutanugarn hit all 14 fairways in the second round.
"I don't think it's like so good, my game," Jutanugarn said about the tree-lined course. "Because to me it's a little bit narrow and I can't hit my driver. But right now I feel more confident because I can hit my iron on the fairway and my 3-wood on the fairway."
She considered skipping the tournament to get another week off.
"But I feel like I'm OK," Jutanugarn said. "I wanted to see how I'm feeling. But after like Monday, it didn't hurt that much. Today, it's getting a lot better."
Ko shot a 69, making four straight birdies in the middle of the round.
She has won the event three of the last four years, the first two as an amateur. The 19-year-old New Zealander won in 2012 at Vancouver Golf Club at 15 years, 4 months to become the LPGA Tour's youngest winner and fifth amateur champion. She successfully defended her title in 2013, winning by five strokes in Edmonton. Last year back at Vancouver as a pro, she beat Stacy Lewis in a playoff.
Ko was second in Rio, five strokes behind Inbee Park.
South Korea's Sei Young Kim (67), Hyo Joo Kim (67), Mi Jung Hur (69) and Chella Choi (71) matched Ko at 8 under.
Henderson dropped a stroke in the completion of a first-round 72 and had a double bogey on the par-3 eighth - her 17th - in a second-round 68. The 18-year-old from Smiths Falls, Ontario, beat Ko in a playoff in June in the KPMG Women's PGA Championship for her first major title, and successfully defended her Cambia Portland Classic title in early July.
"I had massive crowds today and it was so much fun to play in front of them," Henderson said. "I kind of felt their energy, and I got it to minus 6 at one point today and was feeling pretty good. Unfortunately, I had a couple of mistakes coming in."
Alena Sharp (70) and Maude-Aimee Leblanc (69) topped the Canadians at 6 under.
"It's always good to see the Canadian flag on the leaderboard no matter where we are, but definitely this week," Sharp said. "I know in the past we've done well as a group, the Canadians, so it's nice to see halfway through we've got some people up there. Hopefully we can continue it on the weekend."
Sharp shot 68-70, and Leblanc 69-69.
Canadian amateur Jaclyn Lee was 5 under after a 70. The Calgary player is a sophomore at Ohio State.
"These past two days have been really fun, incredible," Lee said. "Just a great experience. It's been a bonus on top of that to play well."
Lewis was 5 under after a 72. Coming off a tie for fourth in Rio, the 11-time tour champion is winless in 57 starts since June 2014. Michelle Wie made the cut on the number with rounds of 71 and 72.