American Tom Pernice fired a one-under 69 to take a one-stroke lead after the third round of the USPGA Tour's AT&T National tournament.
Pernice, who entered the round tied with Jeff Overton after shooting an explosive second-round 63, moved to 10-under-par 200, one shot ahead of American compatriot Steve Stricker.
Australian Nick O'Hern was tied for third at eight-under 202, alongside Americans Overton and Tommy Armour.
Pernice bogeyed the 518-yard, par-four sixth hole but rebounded with a birdie on No.8 to sit at even-par before the turn.
The 48-year-old was even until a birdie on No.17 to remain in the hunt for his third career title.
Stricker came out with plenty of spark, playing his first eight holes at 3-under before a bogey on No.9. He added three more birdies on the back nine - at Nos.10, 13 and 15 - before finishing with another bogey at No.17 to card a 4-under 66 Saturday.
Overton shot a 1-over Saturday. He was 1-under through the front nine, but struggled after the turn with bogeys at Nos.10 and 14 before a double-bogey on the par four 15th.
Overton did close strong with birdies on two of the final three holes.
It has been a trying year for Overton, who has missed the cut in six of his last seven events and 10 of 18 tournaments overall.
Americans Tim Herron, Anthony Kim and Cliff Kresge are in a three-way tie for sixth at seven-under.
Australian Robert Allenby is still in contention at six under.