It was the best round of the season for the 30-year-old Gutschewski, who has made six starts on the PGA TOUR and one previous start on the Nationwide Tour so far in 2007.
He leads Paul Claxton, Brad Elder and Ron Whittaker by one shot.
'It was a good day,' Gutschewski said. 'Things are finally starting to come around for me. It is a crazy game. I don't feel like I'm doing anything different (but) you get a little confidence and it changes things.'
Gutschewski hit all 18 greens in regulation, posting five birdies and an eagle without a bogey. He rolled in a 20-foot eagle putt at the par-5 11th while going 7 under during an 11-hole stretch.
His previous best round in 2007 was a 66 in the first round of the PGA TOUR's Mayakoba Golf Classic, which played opposite the Accenture Match Play Championship at the end of February.
He went on to finish tied for 41st place at the Mayakoba -- one of just three cuts he has made in his seven previous combined starts this season.
Gutschewski tied for sixth at his other Nationwide Tour start, the South Georgia Classic, last month. His only Nationwide Tour win came at the Monterey Peninsula Classic in 2003, his rookie season.
'I just want to play,' Gutschewski defended his recent struggles. 'It is a tough spot to be in. I'm not getting in many tournaments. You want to play but yet you haven't played good enough when you've had the opportunity to improve your status. It is frustrating.'
Among the three players tied for second place at 6-under 64, only Claxton put a bogey on his scorecard Thursday. He eagled the par-5 sixth on the way to tying Elder and Whittaker.
Seven players were tied for fifth place at 5-under 65.
Mark Brooks, the 1996 PGA Championship winner, was near the top of the leaderboard for much of the day, but couldn't overcome a pair of late bogeys and ended at 2-under 68.
Brooks became the 10th golfer to play on the Nationwide Tour after winning a major championship.
His debut came at a familiar venue, too: Hardscrabble is where he won the 1979 Trans-Mississippi Golf Association Amateur Match Play Championship, a title also held by Jack Nicklaus and Ben Crenshaw, among others.