MAUI, January 4, 2014 (AFP) - The reigning PGA Tour rookie of the year Spieth was joined atop the leaderboard by former US Open champion Webb Simpson, Chris Kirk and Michael Thompson at the Kapalua Resort course.
"It's an accomplishment just to be here in the first place. I'm humbled to play alongside these 29 other guys that are champions from the past year," said the 20-year-old American Spieth. "To finally be here, is a cool experience for me."
Jason Dufner is one shot back and tied for fifth place with former Masters winner Zach Johnson, Ryan Moore and Kevin Streelman. They all shot six-under 67.
Matt Kuchar is alone in ninth at five-under, while Bae Sang-Moon of South Korea is one stroke back at four-under 69.
Spieth is one of 13 first-time winners from 2013 in this week's field. He birdied four of his final five holes to shoot a bogey-free round.
Spieth sank an eight-foot birdie putt at the par-three 11th and then had a pair of pars before catching fire.
Spieth two-putted for a birdie after driving the green on the par-four 14th. He birdied the next two holes and closed the round with a 12-foot birdie putt at 18.
In his only other start of the 2013-14 season, Spieth placed 17th at the World Golf Championships-HSBC Champions.
His first career victory came at the John Deere Classic and he went on to post nine top 10 finishes last year.
"We did (play off each other)," said Simpson of his playing partner Spieth. "It's just fun to go out and play with a young guy with a lot of confidence. We just kept making birdies."
Last year's winner Dustin Johnson shot a three-under 70 and is tied for 11th with reigning Masters champ Adam Scott and five others.
The Kapalua event, which is comprised of the winners from the previous season, is the first tournament after an extended break. Because of the Tour's new wraparound schedule it is also the seventh event of the 2013-14 season.
The PGA Tour remains in the Aloha State next week for the Sony Open in Hawaii, which Russell Henley won in 2013.