Michael Putnam, Tim Petrovic share Canadian Open lead at 6-under 64

Mike Weir hits off the seventh tee during first-round play at the Canadian Open golf championship on Thursday, July 24, 2014, in Montreal. (AP Photo/The Canadian Press, Paul Chiasson) (The Associated Press)

Jim Furyk, of the United States, hits off the second tee during first-round play at the Canadian Open golf championship on Thursday, July 24, 2014, in Montreal. (AP Photo/The Canadian Press, Paul Chiasson) (The Associated Press)

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.