Thorpe established the mark of 64 in last year's final round and the score also tied his lowest number of the 2002 campaign. He fired a 64 in the final round of the Kroger Senior Classic two weeks ago en route to a share of eighth place.
'I scored as well as I could have today,' said Thorpe, who won the Senior Tour's first major of the season at The Tradition.
Vicente Fernandez and Wayne Levi share third place at 5-under par, followed by Ed Dougherty, Tom Jenkins and Andy North, who share fifth place at minus-4.
Thorpe nearly broke into red figures at the first, but missed a 10-footer. He finally did go red with back-to-back birdies at two and three, then added a nine-foot birdie putt at No. 6 to make the turn at 3-under 32.
On the back nine, Thorpe's putter went to work. He holed a 25-foot birdie at the 10th and added two long birdies in a row, starting at the 12th.
He reached the 505-yard 17th in two, but missed his 25-foot eagle try, leaving a tap-in birdie. Thorpe rolled home an 18-foot birdie at the last to match his own record and take the first-round lead for the first time since the Instinet Classic in May.
Thorpe's putter was the story Friday and it was a new one that arrived at the course this week.
'This is the best feeling putter I've ever had in my life,' said Thorpe, who was born in nearby Roxboro, North Carolina. 'Putting is what separates guys out here.'
Quigley reached 3-under par after a 12-foot birdie at the par-4 11th. Trouble loomed for Quigley at the 14th when he hit an ugly 7-iron into a bunker and never saved par. He rebounded with a four-foot birdie putt at No. 15, but the best was yet to come for the 55-year-old.
At the 17th, Quigley roped a 4-wood from 235 yards that landed 30 feet from the hole. He ran home the eagle to get to 5-under and took sole possession of second place after a three-footer at the last.
'It's been a while since I've had a low opening round,' said Quigley, whose last opening-round 66 was in the BellSouth Senior Classic at Opryland in mid-June. 'A finish like I had makes it easier for the weekend. You are in a hole if you start off bad.'
Jim Holtgrieve, Tom Purtzer, Jose Maria Canizares, Doug Tewell, Bruce Fleisher and Sammy Rachels share eighth place at 3-under-par 69.
Hale Irwin, the Senior Tour's money leader, shot a 2-under 70 Friday and is part of a group in 14th that includes Ben Crenshaw, Larry Nelson and U.S. Senior Open winner Don Pooley.
Bruce Lietzke, the 2001 champion, opened his title defense with an even-par 72.
Full-field scores from SAS Championship