Michael Putnam and Tim Petrovic fired matching 6-under 64s on Thursday to share the lead at the RBC Canadian Open.
Petrovic has one career win on the PGA Tour, while Putnam is seeking his first win on tour.
Kyle Stanley and amateur Taylor Pendrith each carded a 5-under 65 at Royal Montreal Golf Club to share second place.
Former Masters winner Charl Schwartzel headlines a group of 11 players tied for fifth at 4-under 66. He is joined by Justin Hicks, Charlie Wi, Greg Chalmers, Nick Watney, Robert Allenby, Troy Merritt, Bo Van Pelt, Dicky Pride, Jason Bohn and Joel Dahmen.