Guy Boros, who held the lead after each of the first two rounds, carded a 2-under 70 to finish alone in second place at 18-under-par 198. Ryan Palmer was one shot further back at 17-under-par 199.
Ogilvie was four shots behind Boros to start the day at Yankee Trace and torched the front side to surge to the top of the leaderboard. He opened with back-to-back birdies from the first and at the par-4 fourth, Ogilvie tallied the first of four consecutive birdies to go out in 30.
The 29-year-old made the turn at 18-under and continued his fine play with a pair of birdies starting at the par-4 11th.
Ogilvie found trouble with a bogey at the par-4 17th but was able to maintain his lead with one round to play.
'I got off to a really good start and Guy's putter wasn't working. The magic wasn't there for him like it was the first two days,' said Ogilvie.
Ogilvie is now 18 holes away from earning a spot on the PGA Tour through the 'Battlefield Promotion,' which allows a player who wins three times in a season on the Nationwide Tour to advance to the main circuit.
'You try not to think about that on Thursday and Friday,' said Ogilvie. 'Saturday, it enters your mind a little bit.'
Boros, who is seeking his second victory of 2003, held a commanding lead after opening the tournament with back-to-back rounds of 64. On Saturday, Boros got an extra boost out of the gate with an eagle at the par-5 first.
He added a birdie at the fifth to reach 19-under but stumbled with a bogey at the par-4 eighth. Boros dropped another shot with a bogey at the 17th but recovered with a birdie at the last to finish well within reach of Ogilvie.
'I think I lipped out four or five today and just didn't have the confidence I had the first two days,' said Boros. 'I still have a chance to win tomorrow.'
Zach Johnson posted a 5-under 67 to join D.A. Points in a tie for fourth at 15-under-par 201.
David Morland and Rick Price were one shot further back at 14-under-par 202. They were followed by Boo Weekley, Stephen Gangluff and Bobby Gage at minus-13.