'I've just been ready to go,' Klauk stated. 'It's been a long time since I've gotten off to a decent start. I just want to get to the next level.'
Scott Dunlap is alone in second at minus-five at Panama Golf Club.
Ben Bates, a two-time winner on the Nationwide Tour, opened with a 4-under- par 66. He was joined in third place by Pablo Acuna and Brendon De Jonge.
Klauk parred his first two holes before running home a 30-foot birdie putt on the par 4 third. He came right back with an eagle on the fourth, from 35 feet out, to quickly move to minus 3.
The 30-year-old settled in with five straight pars from the fifth. Klauk dropped in back-to-back birdies from the 10th to move to five-under.
Klauk faltered to his only bogey at the par 4 14th. He quickly atoned for that mistake with a birdie on No. 15. He closed with a 40-foot birdie putt at the last to secure the first-round lead.
'I've been hitting the ball very well, but my coach and I have been working on the mental side of the game,' said Klauk. 'I had some shoulder surgery and some health issues the past couple of years and sometimes it's not easy to get your confidence back. A lot of it is just believing in yourself.'
Dunlap tripped to a bogey on the second, but came back to birdie each of the next 3 holes. Another bogey at the seventh dropped Dunlap to minus 1.
Around the turn, Dunlap moved to minus-2 with a birdie on the par 4 11th. He parred four straight before a hot stretch run.
Dunlap birdied the par 416th and followed with birdies on 17 and 18 to finish one behind Klauk.
Matthew Every, Chris Smith, Kim Felton and David Morland IV are tied for sixth place at 3-under-par 67. Jeff Brehaut