Joe Ogilvie, Doug LaBelle II and Roland Thatcher share second place at 14- under-par 202.
Elliott started fast with a birdie at the first at Fox Den Country Club. He went on to notch back-to-back birdies from the fifth to move to minus-14. Elliott made it three birdies over a four-hole stretch when he ran home a birdie at the eighth.
The two-time winner on the Nationwide Tour played steady golf the rest of the way. He ran off nine straight pars from the ninth to maintain his lead. Elliott extended his lead to two shots with a birdie at the last.
'For some reason I was more relaxed today than yesterday,' said Elliott. 'I played really well on the front but then I was misjudging a couple shots on the back.
'It's never easy out here, that's for sure,' said Elliott, who was locked out of his hotel room for two hours Saturday morning. 'The pressure will be building tomorrow. If I shoot even-par tomorrow with a two-shot lead, I'll lose.'
Ogilvie tied for the best round of the day with a 6-under 66. He began his day with a birdie at the first before back-to-back birdies from the fourth.
Ogilvie, who won the Jacob's Creek Open earlier this year, bogeyed the par-3 sixth to halt his momentum. Around the turn, he eagled the par-5 10th to climb to 12-under.
He moved within one stroke of the lead with a birdie at the par-4 14th. Ogilvie closed his round with his fifth birdie of the day at the last and the money leader is in position to extend his lead on the tour's money list.
'I'm trying to win but leading the money list in July isn't all that important,' said Ogilvie. 'I know the other guys are playing very well so I may need 66 or 67 tomorrow to win.'
LaBelle birdied three of his first five holes to get to 13-under. He settled down from there as his next birdie came at the 10th. He bogeyed the 17th, but responded with a birdie at the last for a 4-under 68.
'This is the first good Saturday I've had all year so I'm really happy,' said LaBelle. 'It's 72 holes, so I've still got 18 to go.'
Thatcher started the day tied with Elliott for the lead. Like the other leaders, Thatcher birdied the first hole. He also birdied the third and sixth but trouble loomed.
At the par-4 eighth, Thatcher dropped two shots due to a double-bogey. On the back side, he recovered those strokes with a pair of birdies on his way to a 3-under 69.
'Unfortunately, I couldn't keep pace with John,' said Thatcher. 'But I struggled down the stretch so I'm happy I didn't give anything away.'
Craig Bowden, Chris Couch and Vaughn Taylor share fifth place at 12-under-par 204. Guy Boros is one shot back at minus-11 after a 2-under 70.