Michael Putnam and Tim Petrovic shared the first-round lead in the Canadian Open on Thursday, shooting 6-under 64 in sunny conditions at rain-softened Royal Montreal.

Canadian amateur Taylor Pendrith and Kyle Stanley were a stroke back, and former Masters champion Charl Schwartzel, Nick Watney and Robert Allenby topped the group at 66.

Two-time champion Jim Furyk and Canadian David Hearn shot 67, and defending champion Brandt Snedeker had a 69.

Dustin Johnson struggled to a 74, and John Daly had a 76.