Charles Warren, who won the Canadian PGA Championship two weeks ago, fired a 65 to join Chris Anderson in a tie for second at 15-under-par 201. Doug Barron, Chris Tidland and Lee Porter were one shot further back at 14-under-par 202.
Elliott, a two-time winner on the Nationwide Tour, picked up where he left off after the second round at Champions Run with four birdies over his first seven holes to begin to distance himself from the field. Elliott wasn't out of the woods yet, however, and a double-bogey at the par-4 ninth dropped him back to 15 under around the turn.
The 40-year-old recovered at the very next hole and reached the green in two at the par-5 10th. Elliott took two putts for a birdie and parred his next four holes before missing the green with his approach at the par-4 15th.
Elliot chipped in for birdie and picked up a birdie at the following hole. Elliott then two-putted for a birdie at the par-5 17th to make it three in a row and open a four-shot edge over his closest competitors.
At the par-4 closing hole, Elliott hit his drive in the rough and scrambled to a bogey, but still managed to hold a comfortable advantage with one round to play.
'I'm real comfortable out there,' said Elliott. 'I hit my irons really good again today and my short game has been really good.'
Warren birdied each of the first two holes and added three more birdies on the front nine to make the turn at minus-13. He two-putted for a birdie at the 10th and tallied another birdie at the 14th close in on Elliott.
The 29-year-old hit his tee shot in a bunker at the par-3 16th and could not get up-and-down for par. After the bogey, Warren missed the green again with his second shot to the par-5 17th. He recovered well, however, and chipped his third shot from the rough within a foot of the hole for a tap-in birdie.
'One of my goals today was to play well enough to get in that last group,' Warren said. 'It will be fun tomorrow. This is always a shootout on Sunday. But if I can progress from today to tomorrow I think I'll be okay.'
Anderson ran off three straight birdies starting at the second, but found trouble with a bogey at the seventh. Anderson responded with back-to-back birdies from the ninth and a 14-footer for birdie at the 12th lifted him to minus-15.
Anderson, who won this year's Carolina Classic, faltered with a bogey at the 16th, but came right back with a birdie at the 17th to stand within three of the leader after a round of 67.