Washington - Robby Shelton shook off opening-day nerves to card an eight-under par 62 and take a two-shot first round lead on Thursday at The Greenbrier, his first tournament as a PGA Tour member.
"Last night it was tough to sleep," Shelton admitted.
"I've been waiting for this moment all season."
But the 24-year-old from Alabama, who won twice on the developmental Korn Ferry Tour last season, looked right at home as he fired nine birdies with just one bogey.
He capped his round on the Old White TPC in White Sulphur Springs, West Virginia with a birdie at the ninth hole.
Shelton was two strokes ahead of defending champion Kevin Na, Scott Harrington, Mark Hubbard, Lanto Griffin and Zack Sucher.
Another 10 players were tied at 65, a group that included Chile's Joaquin Niemann and South Korea's Kang Sung.
World No 10 Bryson DeChambeau, the highest ranked player in the field, carded a 68 as the PGA Tour's 2019/20 season got underway with the game's top players still resting.
The leaderboard featured a host of players who, like Shelton, spent time last season on the developmental Korn Ferry Tour, formerly known as the Web.com tour.
But Shelton isn't technically a rookie. He's categorized instead as a "first time member" on the tour because he made eight starts during the 2016/17 season - when he was unable to gain his tour member status.
"I think (during) my sponsor exemptions and stuff I thought I had to change my game and try to play with the big boys," he said. "Now, I just know it's golf. (I've) been through the Mackenzie Tour and the Korn Ferry Tour so I know what my game has.
"And if I can just get to that a lot sooner, that's the goal."
Na carded seven birdies and one bogey to join the group sharing second. The Korean-American is back in action after opting out of the BMW Championship last month as he and his wife, Jullianne, welcomed the birth of their second child, son Leon LeeWoo Na.
That meant Na couldn't make the field for the season-ending Tour Championship, but he was also well-rested for his defence of a title he won in July of 2018, with the extra-long gap coming because the tournament was shuffled around as the tour revamped it schedule.
"I'm ready to go and excited about this new season," Na said.
"Not only am I excited, the first tournament of the year I'm defending so there is more excitement."
Leading first-round scores on Thursday in the PGA Tour's The Greenbrier at White Sulphur Springs, West Virginia (USA unless noted, par-70):
62 - Robby Shelton
64 - Scott Harrington, Mark Hubbard, Kevin Na, Lanto Griffin, Zack Sucher
65 - Joaquin Niemann (CHI), Harold Varner, Jimmy Walker, Kang Sung (KOR), Brian Harman, Sam Ryder, Scottie Scheffler, Bronson Burgoon, Doug Ghim, Rob Oppenheim