Brooke Henderson stays in the hunt at LPGA's CPKC Women's Open in Edmonton

Brooke Henderson has work to do, but runway to do it at the CPKC Women's Open in Edmonton.

The defending champion from Smiths Falls, Ont., seeking a third career win in Canada's LPGA tournament, shot a second-round 68 on Friday to sit 5-under par.

With two rounds to play, Henderson was four strokes back of clubhouse leader Soo Bin Joo of South Korea at 9 under at Edmonton's Royal Mayfair Golf Club.

Henderson was 7 under before a pair of back-nine bogeys. Her second-last tee shot drifted left and struck a spectator. Henderson apologized to the woman and gave her a golf ball.

Calgary's Aphrodite Deng, who was the tournament's low amateur last year in Mississauga, Ont., capped her round with back-to-back birdies for a 67 to get to 3 under.

• Yamashita early leader at CPKC Women's Open, Canadian teens and Henderson chasing

The top 65 players and ties make the cut at the $2.75-million US event. Canadian teenagers Anna Huang of Vancouver and Michelle Xing of Richmond Hill, Ont., who started the day three shots off the lead at 5 under, had afternoon tee times.