John Riegger fired an 8-under 64 on Saturday to grab a 3-stroke lead following two rounds of the Boeing Classic.
Riegger finished 36 holes at TPC Snoqualmie Ridge at 11-under-par 133. He will try for his first career win on the Champions Tour on Sunday.
"It was a great day all in all. I basically played the same way I played yesterday, I got off to a better start today and just kind of let the momentum build and let the golf course come to me," said Riegger.
Two-time winner this season Bernhard Langer (68), Tom Lehman (67), Kirk Triplett (68) and Bobby Clampett (69) shared second place at 8-under.
John Cook (68), who won the season-opening Mitsubishi Electric Championship, sat alone in sixth at 7-under 137, while 3M Championship winner Tom Pernice, Jr. (68), John Huston (68) and Duffy Waldorf were tied for seventh at minus-6.
First-round leader Bart Bryant struggled to a 3-over 75 during his second round to fall eight strokes off the pace at 3-under 141.
Clampett opened his second round with birdies at the first and fourth to move to 7-under and claim the outright lead from Bryant, but Langer followed a birdie at the first with consecutive gains at the fourth and fifth to meet him there.
Langer would bogey the sixth to fall a shot off the pace before Triplett recorded birdies at the first, fifth and sixth, and Riegger rolled in gains at Nos. 1, 2, 7 and 8 to make it a three-way tie for the lead.
After Bryant joined the group with a birdie at the sixth, Langer jumped ahead of the pack with an eagle at the eighth.
Riegger briefly joined Langer at 8-under with a birdie at the 10th, but he followed with a bogey at the 11th to fall behind.
Langer dropped a shot at the ninth to also fall to 7-under, allowing Clampett to claim the lead at minus-8 with his birdie at the eighth. Riegger then birdied the 12th to join Clampett atop the leaderboard.
Clampett would briefly pull ahead with a birdie at the 12th, but followed with a bogey at the 13th to fall back to 8-under.
Riegger then moved ahead for good with a pitch-in eagle at the 15th, and a birdie at the 16th moved him three clear of the field at 11-under.
He parred his final two holes to stay there.
"There's a lot of guys that are capable of going out and shooting 63 and (64) on this golf course, so I've got to keep controlling what I do and I can't control what anyone else is doing," Riegger said about his approach for Sunday's final round.
NOTES: Riegger is making just his fifth start on the Champions Tour ... Riegger is trying to become the fifth rookie and first-time winner on tour this season ... Six of 16 Saturday leaders have go on to win this season, including the last two events ... Scott Hoch withdrew before the start of the second round with an ankle injury.