Oregon, which began the trend of colorful uniform combinations, had its players wear pink helmets, shoes and socks to mark Breast Cancer Awareness Month.
Washington State tried to counter the Duck's high-powered offense by passing -- a lot. Cougars' quarterback Connor Halliday set a Football Championship Series record with 89 pass attempts.
He completed 58 of the throws for 557 yards and four touchdowns. He was also intercepted four times.
Oregon's more balanced attack saw Mariota completed 23-of-32 passes for 327 yards. The Ducks (7-0, 4-0 Pac-12) rushed for another 383 yards and sixth touchdowns. Byron Marshall had 192 yards and three scores on 21 carries and Thomas Tyner added 99 yards and two touchdowns on seven rushes.
Oregon scored 14 points in every quarter but the first when the Ducks put up 20.
Washington State (4-4, 2-3) trailed 13-0 7 minutes into the game but was just down 34-24 at halftime. Mariota had a scoring pass and Marshall ran 30 yards for a score that pushed Oregon to a 48-24 edge going into the fourth quarter.
The Ducks had two more scores early in the fourth period including Terrance Mitchell's 51-yard interception return for a touchdown, for a 38-point bulge.