Steve LeBrun holed out from the fairway for eagle at both the 17th and 18th holes Saturday. He also shot an 8-under 63 in the third round and is alone in second at minus-17.
Roger Tambellini posted a 3-under 68 and is alone in third at 16-under-par 197.
On Friday, Jason Gore became the third player in Nationwide Tour history to fire a 59. Saturday was a different story for the golfer who played in Sunday's final pairing at this year's U.S. Open.
He was cruising along at 5 under for his round until the 13th when he hit his approach from 130 yards out in the fairway long and right. Gore ended up with a double-bogey and a round of 3-under 68.
Gore is tied for fourth place with second-round leader Jon Mills, who managed an even-par 71. The duo is knotted at 15-under-par 198.
Petersen was two-under on his round when he ran in a 7-foot birdie putt at the seventh. That kickstarted a run of amazing golf that put Petersen atop the leaderboard.
He holed a 45-foot birdie putt at the par-3 eighth, then birdied No. 9. Petersen two-putted from 35 feet for a birdie at the 10th, his fourth in a row.
Petersen parred the 11th, but tallied another birdie at the 12th. He parred his next four holes, but recorded his eighth birdie of the round at the par-5 17th when he came up short with his second, but pitched to 3 feet and converted the birdie putt.
Petersen has now gone through 54 holes without a bogey.
'You have to realize that every hole, if you're hitting it good, is a birdie hole,' said Petersen, whose only Nationwide Tour victory came in 2000. 'I feel like I can birdie every hole.'
LeBrun actually bogeyed his first three holes on Saturday, but eagled the fourth and amassed three more birdies before making the turn. He birdied 12 and 14, but the best was yet to come for the 27-year-old.
At the par-5 17th, LeBrun hit a wedge for his third shot and the ball took two hops before rolling 10 feet into the hole. Then, at the 18th, LeBrun's 8-iron approach took two hops and ran into the cup for back-to-back eagles.
'That's unbelievable,' said LeBrun, who is winless on the Nationwide Tour. 'I hung in there. I played 11 under the last 15 holes. I've been playing really good and those first three holes are pretty tough. I wasn't too upset. Anything can happen and it did.'
Greg Kraft (64) and Bubba Dickerson (65) are knotted in sixth place at 14-under-par 199. John Mallinger shot a 5-under 66 and is alone in eighth at minus-13.