Reigning champion Tom Lehman posted a four- under 68 Saturday to grab a two-stroke lead after 54 holes of the Tradition, the second major of the year on the Champions Tour.
Lehman, who beat Peter Senior in a playoff last year, finished three rounds at 10-under-par 206.
The 53-yeard-old has already won two majors on the senior circuit after winning his only regular tour major at the 1996 British Open Championship.
And he'll again have to fend off Senior if he is to become the first repeat winner since Gil Morgan won in 1997-98.
Senior matched the low round of the week with his six-under 66 in round three. That helped Senior jump into a share of second with Jeff Sluman (70) at minus- eight.
Second-round leader Bill Glasson faltered to a two-over 74 to slip into a share of fourth place at seven-under-par 209 at Shoal Creek.
Glasson was joined in fourth place by two-time champion Fred Funk (71), Russ Cochran (72) and Brad Bryant (71).
With as many as six different players owning at least a piece of the lead on Saturday, Lehman's steady play gave him the lead with one round to go.
Lehman eagled the par-five third from eight feet out to quickly jump to minus- eight. After five consecutive pars, he converted about a 30-foot birdie effort on the ninth to grab a piece of the lead.
The five-time winner on the Champions Tour moved to 10-under for the first time with a birdie on No. 14.
Lehman tripped to a bogey two holes later, but still led by one. He came right back with an eight-foot birdie putt on the par-five 17th. Lehman parred the last to lead by two.
"It was a good day. I got off to a real good start. I played especially well the first eight or nine holes," Lehman stated. "Seems like I always kind of seem a little uncomfortable on some of those holes early in the back nine - 11 and 12 have always been a little bit awkward for me. So I feel like if I could get through those holes, I feel pretty good about the rest of the way."
Senior flew up the leaderboard on the front nine. He posted birdies at two and three to get to minus-five. Last year's runner-up wrapped birdies at six and eight around an eagle on No. 7.
That spurt got Senior to eight-under. He picked up another stroke on the 11th, but tripped to a bogey on No. 12. Senior parred the final six holes to share second.
"It was essential for me to shoot something decent today to have a chance tomorrow," Senior admitted. "I didn't realize I was going to start as well as I did, birdieing two of the first three."
Sluman was even-par through four holes with bogeys on the second and fourth to go with an eagle at the third. Sluman carded a birdie at the sixth before making four pars in a row. He birdied the par-five 11th before finishing with seven consecutive pars.
NOTES: Lehman's win at this event last year was his last Champions Tour victory...Lehman, who is the only player in the field with three rounds in the 60s, is hoping to become the first player since Allen Doyle at the 2006 U.S. Senior Open to successfully defend a major championship title...Glasson hopes to snap a streak in which the last 36-hole leader to win this crown came in 2003...The winner of the last 20 Champions Tour events has come from the final group, but just nine of 21 54-hole leaders has won this title.