In his first round since winning the British Open on Sunday, Ernie Els could not finish strong like he did to win a second Claret Jug.
Els made a triple-bogey 7 on the 11th at Hamilton G&CC en route to 2-over 72 that leaves him 10 shots back of Scott Piercy after the first round of the RBC Canadian Open.
Piercy eagled both par 5s on Thursday, made five birdies and a bogey to shoot 63 and take a one-shot lead over Greg Owen and William McGirt.
Robert Garrigus is alone in fourth at 6 under par.
Seven players are tied at 5 under, including Vijay Singh, Troy Matteson, Bo Van Pelt, Jhonattan Vegas, Charl Schwartzel, Stuart Appleby and Gavin Coles.