John Elliott is alone in second at 7-under, while David Gossett stands five shots off the lead at minus six.
Quigley, five shots ahead of the field when he teed off Saturday, mixed two birdies, two bogeys and a double-bogey over the first 14 holes Saturday to fall into a tie for the lead at 8-under with Elliott, who rebounded from a bogey at the fifth hole with five birdies over the next nine.
The situation seemed to get worse for Quigley, who drove into a fairway bunker at No. 15. With 205 yards to the pin from the sand, he promptly ripped a 3-iron to three feet and converted the birdie effort. Elliott bogeyed the same hole to give Quigley a two-shot edge.
'It was 50-50 to hit the lip with my club,' said Quigley. 'Somehow, it came out perfect. With 200 balls, I couldn't do that again.'
Quigley added two birdies at his final two holes to get out to a four-shot lead. Should he hang on to win Sunday, Quigley would become the first Buy.com Tour player to go wire-to-wire for a victory since Kelly Gibson won the 1999 Oregon Classic.
'I'd like to have a 30-shot lead,' said Quigley. 'Out here, you never know what's going to happen. I figured if I can go out and shoot under par today and tomorrow, I'd have a pretty good chance to win.'
Although Elliott leads the field in greens in regulation, he has struggled with his putter. He has needed 92 swipes with the flatstick thus far, which does not even rank him in the top-50 for the tournament.
'I missed a few putts today,' said Elliott, who shot a three-under 69 on Saturday. 'It was better than the first two days, so I'm getting closer.'
Gossett, the 1999 U.S. Amateur champion, rebounded from back-to-back bogeys on the back nine with two birdies in his last four holes to post a 2-under 70.
Andrew Morse, who holed his sand-wedge approach at the eighth hole for an eagle, fired a 6-under 66 on Saturday and shares fourth with Emlyn Aubrey, Richard Zokol, David Kirkpatrick, Ben Bates and Tim Petrovic. The group rests at minus four.
Full-field scores from the Buy.Com Arkansas Classic