Ji, who shared the overnight lead with Jenny Shin, recovered from a bogey on the par-4 5th with four birdies for a total of 10-under 206. The South Korean veteran is looking for her first win since the 2009 U.S. Women’s Open.
Lydia Ko carded seven birdies against a bogey and a double bogey on the 17th for the day’s lowest round of 68 and is tied for second with Shin at 4-under 212.
“It was pretty tough out there with the wind being pretty strong and starting from the first hole,” Ko said. “It kind of progressively picked up. I played solid and made a few good putts. A little careless plus little mistakes on 17, but it’s always nice to be able to finish with a birdie on the last.”
Shin had three bogeys on her way to a 75 but the LPGA Tour veteran wasn’t ruling out a surprise on Sunday.
“Everybody has a bad day,” Shin said. “Everybody has a good day. That was my bad day. So hopefully tomorrow I can come back with a solid round and hopefully try to catch the leader.”
Cristie Kerr shot a 70 and was tied for fourth in a group that included Brittany Altomare (75).
Top-ranked So Yeon Ryu and No. 2 Sung Hyun Park, the U.S. LPGA Tour rookie of the year, struggled to find their rhythm. Ryu finished with a 75 for a share of 16th place, and Park was 6 over after a 73.
Hamilton’s Alena Sharp is the top Canadian. She sits 2 under after shooting a 71 in the third round.
Brooke Henderson of Smiths Falls, Ont., is 4 over after also shooting a 71.