Zach Johnson, Rory Sabbatini and Brian Harman all carded a 63 on Thursday to tie for the lead in the John Deere Classic.
Harman recorded nine birdies and just one bogey on a scoring-friendly day in Silvis, while Johnson and Sabbatini both managed to get through their respective rounds of eight-under-par without blemishing their cards.
It was tight at the top of the leaderboard at the end of day one, with Todd Hamilton, Steven Bowditch and William McGirt sitting just one shot behind the leaders.
Brendon de Jonge and David Toms are in a group currently one shot further back, while three-time winner Steve Stricker managed to reach three-under.
Defending champion Jordan Spieth started disappointingly, but birdies on 16 and 17 allowed him to get back to level par.
