Rybarikova won 95 percent (20-of-21) of her first-service points en route to a 6-1, 6-1 victory over Pavlyuchenkova, which took only 65 minutes to complete.
The Slovakian added the Washington title to wins in Birmingham in 2009 and in Memphis last year.
Pavlyuchenkova, meanwhile, came up short in her bid for a fourth career WTA championship.
2014: The Year in Fashion [PHOTOS]
UPI Sports Results for September 19, 2014