JACKSON, 7 Nov, 2014 (AFP) - Cappelen, who won his first-ever start on the Web.com Tour earlier this year, seized a two-shot lead in Thursday's opening round of his first PGA Tour event at the Sanderson Farms Championship.
Denmark's Cappelen fired a seven-under 65 as the first round was suspended due to darkness.
The 24-year-old, who turned pro this year, is playing on a sponsor's exemption at the Country Club of Jackson course.
"I have to make it look like they made the right decision. That's important to me, proving that I can play with these guys," said Cappelen.
Five months ago he won the Air Capital Classic on the Web.com Tour, but failed to earn his US PGA Tour card for 2014-15.
After opening Thursday with a three-putt bogey, he made eight birdies the rest of the way.
"It felt easy today," he said.
Robert Streb, who won The McGladrey Classic two weeks ago, opened with a 67. He was joined in second place by Scott Pinckney and Canada's Nick Taylor.
Streb has been one of the hottest players heading into this event.
"I kind of picked up where I left off," he said.
Three former major champions -- David Toms, David Duval and Ben Curtis -- are among those tied for fifth at four under. They stand alongside Charlie Wi, Alex Prugh, John Rollins, William McGirt, Jason Bohn and Andres Gonzales.
Woody Austin, who won this title the last time the event was played in 2013, carded a two-under 70 and was part of a large group tied for 27th place.
Play was suspended for the day due to darkness and will resume Friday morning. Fifteen players in the field of 132 were unable to finish.
Leading scores after Thursday's first round of the USPGA Tour's Sanderson Farms Championship (USA unless noted, par-72, play was halted because of darkness):
65 - Sebastian Cappelen (DEN)
67 - Nick Taylor (CAN) , Robert Streb, Scott Pinckney
68 - David Duval, David Toms, John Rollins, Jason Bohn, Charlie Wi (KOR), Ben Curtis, Andres Gonzales, Alex Prugh, William McGirt
69 - Lee Janzen, Heath Slocum, David Hearn (CAN), Tom Gillis, Brendan Steele, Oscar Fraustro (MEX), Jason Kokrak, Jim Herman, Zack Sucher, John Peterson, Mark Hubbard