Lowry a shot off Canadian Open lead as Koepka fires eight birdies

Brooks Koepka made one of his strongest starts since his return to the PGA Tour, making eight birdies and two bogeys to earn a share of the lead with a six-under 64 at the Canadian Open.

Ireland's Shane Lowry is still in the hunt for his first win of the PGA Tour season, finishing one shot off the lead on five under, but will be disappointed with his performance on the back nine, finding a single birdie on the 18th after notching four on the front nine of the course.