OAKVILLE, Ontario —
Sweden’s David Lingmerth was a stroke back after a 65, and Matt Kuchar and Jason Bohn were 12 under. Kuchar had a 64, and Bohn shot 66.
“The birth of a child is a truly magical, special thing. You may get it once in your lifetime. It just doesn’t happen that often,” Kuchar said. “Hunter right now is playing some of the best golf in the world. It kind of gives the rest of us a chance with him not in the field.”
Dustin Johnson also shot 63, good for a tie for fifth at 11 under with John Merrick (72), Greg Owen (67), Charley Hoffman (67) and Kyle Stanley (66).
Merrick, two strokes behind Mahan on Friday after matching the course record with a second-round 62, played alone in the third round after Mahan withdrew.