Marcus Mariota threw for 303 yards and two touchdowns and ran for a career-high three scores, and No. 3 Oregon likely secured a playoff spot by overwhelming eighth-ranked Arizona 51-13 in the Pac-12 championship game Friday night.

On a rainy night in Silicon Valley, Oregon wiped out the Wildcats in front of a sparse but rowdy pro-Ducks crowd — announced as 45,618 — that sprinkled the red seats at $1.3 billion Levi's Stadium bright yellow and green.

Mariota also boosted his credentials for the Heisman Trophy as the Ducks turned the patchy field into their personal playground.

Oregon outgained Arizona 640 to 224 yards.

The selection committee will announce the four-team playoff field Sunday, and Oregon is almost surely guaranteed a berth. The Ducks (12-1) entered the week ranked second in the playoff standings.