Australia's Cameron Percy sits third but American star Zach Johnson has taken control of the Kaulig Companies Championship, the fourth of the five majors on the PGA Tour Champions.
Johnson shot a seven-under 63 third round on Saturday at rain-softened Firestone Club in Ohio to take a four-stroke lead from defending champion Miguel Angel Jimenez, who posted a 62.
"It was for the taking today," Johnson said after getting to 13 under 197. "It was wet. It was pretty much point and shoot and stop."
In those conditions, Percy's even-par 70, with two birdies offset by two bogeys, was not enough to keep pace and he was seven shots behind the leader in outright third, a shot ahead of Darren Clarke (68) and Tag Ridings (68).
The 50-year-old Johnson has two victories in eight senior starts this season. He skipped the US Senior Open last week to play in the PGA Tour's John Deere Classic, where he tied for ninth.
In cloudy conditions with a high of 83 degrees, Johnson played the front nine in 5-under 30 and added two birdies on the second nine.
"The front nine was as solid of nine holes as I've played in I couldn't tell you how long," Johnson said.
Jimenez, the 62-year-old Spanish star, shot his age for the first time as he led the chase after Johnson.
"Every time you can shoot your age is great," Jimenez said.
Michael Wright (69, tied 31st at one over) was best of the other Australians, with Steve Allan (70) at two over, Stuart Appleby (72) three over, Greg Chalmers (73) and Richard Green (68) four over, Rod Pampling (74) six over, Mark Hensby (76) nine over and Scott Hend (71) 12 over.
Johnson won the James Hardie Pro Football Hall of Fame Invitational in his first senior start and took the Principal Charity Classic in his native Iowa in his last. He won 12 times on the PGA Tour, highlighted by major victories in the 2007 Masters and 2015 British Open.
"I played 54 good ones, I've got 18 more to go and I've got to play good," Johnson said. "You never know what could happen tomorrow depending on the conditions, wind or lack thereof."
Charles Schwab Cup leader Stewart Cink was tied for sixth at five under after a 68. He has four wins in 11 starts this season.
Three-time tournament winner Bernhard Langer — at age 68 -- shot his age or better for the 45th time, carding a 67. He was tied for 14th at 3 under.