The performance gave the Swede a one-shot lead at 10-under-par 200 at Royal Mayfair Golf Club in Edmonton.
Suzann Pettersen (5-under 65) and defending champion Lydia Ko (67) were tied in second place at 9-under.
I.K. Kim (65) and Brittany Lincicome (66) were tied for fourth at 8-under 202.
Saturday proved a struggle for second-round co-leader Inbee Park, who carded a 74 to fall six shots off the pace.
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