Allan closed with a birdie for a seven-under 65 on Sunday (local time) and a one-stroke margin over American Stewart Cink.

Allan made a five-foot birdie putt on the par-5 18th at The Club at Snoqualmie Ridge, Washington, then waited to see if Cink could catch him. 

A stroke behind going into the final hole, Cink left a greenside bunker shot on the lip and made a par for a 70.

The 51-year-old Allan finished at 15-under 201. He won the the Galleri Classic at Mission Hills in the California desert in March and the Dick's Open last month in Endicott, New York.

Ernie Els and Darren Clarke tied for third at 13 under, each shooting 66. Alex Cejka was another stroke back after a 67.

Local favourite Fred Couples tied for 47th at one over after a 75 in just his seventh senior start of the season.