Park's 10-under-par round gives her a one-shot lead over Angela Stanford, who shot a 64 on Saturday at Grey Silo Golf Course in Waterloo, Canada.
Scotland's Matthew shot a relatively disappointing three-under-par 68 on Saturday after opening with rounds of 63 and 64, with a double bogey on the 12th proving critical. She will start the final day two shots off the lead.
Park claimed her performance was down to a red-hot putter, and said that she hadn't even been keeping track of how many under par she was.
“I didn't realise it,” Park said after a round containing an eagle and eight birdies. “My long putting was pretty awesome. I just tried to trust it.
“It's going to be hard (on Sunday). I mean, everybody can hit it 10 under, 9 under any time, so I cannot breathe… I have to keep it going.”
- Sports & Recreation
- Angela Stanford
- Grey Silo Golf Course