Webb Simpson hit a bogey-free round of 61 to take a one shot lead after the first round of the Greenbrier.
The American went out in 31 with three birdies, then hit a birdie-birdie-eagle on his way to a round of nine under.
South Korean Whee Kim is a shot behind at West Virginia, followed by Chilean Joaquin Niemann on seven under.
Simpson sliced in an 18-foot chip on the par-5 12th for eagle and told the PGA Tour website: “I’m feeling really good and confident.
“Putts are going in and so I feel really good about my game.”
American Kelly Kraft sits fourth on six under, while four Americans follow a shot behind and 15 a shot further back including Phil Mickelson.
Seamus Power of Ireland went round in an even 70 and is tied for 88th.