John Riegger carded a 4-under 68 on Sunday to claim a 2-stroke victory at the Boeing Classic.
Riegger, who was making just his fifth career start on the Champions Tour, earned his maiden tour victory at 15-under-par 201.
"I knew it was going to be a long, hard day," said Riegger. "I just really didn't have my feel today, but just tried to hang in there and tried to not do anything crazy and just be patient. And it paid off."
John Cook fired a 6-under 66 during his final round at TPC Snoqualmie Ridge to move into second place at 13-under, while Fred Couples also shot 66 to finish in third at minus-11.
Two-time winner this season Bernhard Langer (70) highlighted a group of players sharing fourth place at 10-under 206. He was joined by John Huston (68), Gene Sauers (67), Tom Pernice, Jr. (68), Duffy Waldorf (68), Bobby Clampett (70) and Tom Lehman (70).
Riegger entered the final round holding a 3-stroke lead over his nearest competitor, and he wasn't threatened on Sunday until Langer, who was playing with Riegger in the final group, rolled in his third straight birdie at the fourth to pull within a stroke of Riegger at 11-under.
Riegger had recorded five pars and a birdie over his first six holes to reach 12-under.
After Langer bogeyed the fifth to drop two strokes behind Riegger, Riegger dropped a shot at the seventh to fall to minus-11.
Clampett then poured in his fifth birdie of the day at the eighth to meet Riegger atop the leaderboard before Langer raced ahead with back-to-back gains at the eighth and ninth.
A 2-stroke swing at the 11th allowed Riegger to regain the lead as he birdied the hole to move to 12-under, while Langer tripped to a bogey there to fall behind.
Langer would not threaten the lead again, dropping shots at the 13th and 15th to fall off the pace.
Cook, meanwhile, had raced up the leaderboard with birdies at the first, fourth, fifth, 12th, 15th and 16th around a bogey at the ninth to meet Riegger in the lead at 12-under.
But Riegger caught fire down the stretch to pull away, recording consecutive birdies at the 15th and 16th to claim a 2-stroke lead over Cook.
Cook put a little pressure on the leader with a birdie at the 18th to pull within a stroke, but Riegger followed with a 20-foot birdie at the last to seal the win.
"Pretty strong finish for a guy trying to finish off his first event, so hats off to John," said Cook. "I hung in there. I hit some quality shots coming down the stretch."
NOTES: Riegger is the fifth first-time winner on tour this season .. He is the seventh Saturday leader to go on and win this season and the third straight to do so ... Riegger's last professional win came at the Web.com Tour's 2010 Rex Hospital Open.