American Kris Blanks carded an eight under par 63 to lead the John Deere Classic in Illinois after the first round.
The 38 year old Georgian made ten birdies in his impressive round, and he has a one shot lead from Davis Love III, Matt McQuillan and Steve Marino, who made a late rise up the leaderboard.
Mark Wilson and Kyle Stanley are a further shot behind, with 12 players then on five under, with Steve Stricker and Zach Johnson among them.
Louis Oosthuizen, preparing for the defence of his Open Championship title next week, is level par.
The South African made four birdies but also carded two bogies and a double bogey, leaving him with some work to do already if he is to challenge.
Stewart Cink went round in a one over 72, while Mike Weir and David Duval are four over after 18 holes.
