Marcus Mariota threw for 367 yards and four touchdowns and ran for 39 yards and two more scores to lead third-ranked Oregon to a 47-19 victory over Oregon State in the 118th Civil War game Saturday night.

Oregon (11-1, 8-1 Pac-12, No. 2 CFP) will face Arizona in the Pac-12 championship game Friday at Levi's Stadium in Santa Clara, California.

Freshman Royce Freeman ran for 135 yards and also caught one of Mariota's touchdown passes. Fellow freshman Charles Nelson caught two passes — both touchdowns — for 56 yards, and Byron Marshall had six catches for 131 yards and a score.

It was Oregon's seventh straight win overall and seventh in the series against the rival Beavers (5-7, 2-7), who lost six of their last seven games and failed to become bowl eligible.

Oregon State quarterback Sean Mannion finished his college career as the Pac-12's career leader in passing yards with 13,600 and the school record-holder with 83 touchdown passes.

Mannion threw for 162 yards, with a 20-yard touchdown pass to Hunter Jarmon in the third quarter.

Arizona (10-2, 7-2) clinched a spot in the championship game Friday, when UCLA fell to Stanford and the Wildcats beat Arizona State 42-35. Oregon's lone loss this season came to Arizona at Autzen Stadium on Oct. 2.

Should the Ducks get revenge on Arizona on Friday, they'll be one of the four teams headed to the first college football playoffs.

The six-touchdown night also all but assures that Mariota will be one of the Heisman Trophy finalists announced Dec. 8. Mariota has thrown 36 touchdown passes this season, run for 11 scores and caught a TD pass.

It was his fifth straight game with at least four touchdowns.

Mariota hit Nelson with a 29-yard TD pass on the Ducks' opening series, but the 2-point conversion failed. Matt Wogan added a 30-yard field goal to make it 9-0.

With the scoring pass, Mariota became the only quarterback in FBS history to throw at least one touchdown pass in each of his first 38 games. That's every game of Mariota's career.

The Ducks extended the lead with Mariota's 12-yard screen pass to Freeman, who pulled the ball down with one hand before barreling into the end zone.

Mariota added a 77-yard scoring strike to Marshall to make it 23-0 before running for 23 yards to push the lead to 30-0.

The Beavers scored on a 39-yard field goal just before the end of the first half to make it 30-3. Wogan added a 22-yarder for the Ducks early in the third.

After Mannion's scoring pass to Jarmon narrowed it to 33-10, Mariota ran a yard for his second touchdown on the ground.

Storm Woods, who had been questionable going into the game, ran for a 3-yard touchdown for the Beavers that cut the Ducks' lead to 40-17. Mariota found Nelson again with a 27-yard touchdown pass before Oregon State got a safety with 4:03 left for the final margin.

Oregon was without center Hroniss Grasu for the second straight game because of a knee injury, running back Thomas Tyner, who was seen wearing a boot on his right ankle this week, and receiver Keanon Lowe, who had an undisclosed injury.

Earlier this season Oregon State played spoiler for Arizona State, beating the then-No.7 Sun Devils 35-27 at Reser Stadium and wounding their chances to take the Pac-12 South. But after falling behind early, they couldn't catch up to play spoiler for the Ducks, too.

The Civil War dates to 1894 and it is tied for the fifth most-played rivalry in college football. Oregon leads the series 61-46-10. Last year, Oregon State took the lead with 1:39 left on Victor Bolden's 25-yard touchdown run. But Mariota orchestrated a drive capped with a 12-yard scoring pass to John Huff with 29 seconds to go for a 36-35 Oregon victory.