Troy Matteson has a three-shot lead after the first day of the John Deere Classic in Illinois.
The American holed 10 birdies on his way to a 10-under-par round of 64 on the Deere Run course.
Countryman Ricky Barnes ended the opening round on seven-under, while Gary Christian is one of seven players on six-under after the Englishman hit seven birdies and a bogey.
Elsewhere, Australian Stuart Appleby is joined by nine others one shot further back.