Arizona State raised the stakes with its win over Notre Dame last weekend. The Pac-12 South was in the Sun Devils' control, a spot in the College Football Playoff a real possibility.

All Arizona State had to do was get through its next three games, including two against teams with losing records.

The Sun Devils couldn't get past the first one, losing 35-27 to struggling Oregon State on a chilly night in the Northwest. They dropped six spots to No. 13 when The Associated Press Top 25 was announced on Sunday.

The playoff dreams are done. The hope of winning the Pac-12 South, in someone else's hands.

Considering what was on the line, the loss to the Beavers could go down as one of the biggest letdowns in Arizona State's history — just seven days after one of the program's biggest wins.

"It's very frustrating for us because we've come a long way," Arizona State coach Todd Graham said. "I'm just as proud of our guys right now as I was last week. Like I say all the time, it's very fragile. It's very difficult in college football to bring it every week."

The Sun Devils had taken themselves to the brink of the goals Graham had set for the program when he was hired three years ago.

Following a disappointing home loss to UCLA, Arizona State put together one of the best runs in program history, winning five straight games; four of those against ranked opponents.

It seemed as if it was a run of destiny, too. The Sun Devils beat Southern California on a Hail Mary, Utah in overtime on a field goal and repeatedly found ways to pull out close games.

Arizona State (8-2, 5-1 Pac-12) secured its place in national prominence last week, knocking then-No. 8 Notre Dame out of the playoff race with a 55-31 victory at Sun Devil Stadium. That moved the Sun Devils up to No. 6 in the College Football Playoff rankings and No. 7 in the AP poll.

That left three games before the Pac-12 Championship on Dec. 5: at Oregon State, Washington State and at rival Arizona.

Oregon State, at least on paper, appeared to be the easiest game of the bunch.

The Beavers have struggled this season, entering Saturday night's game with one Pac-12 win and a four-game losing streak.

But with a late start (8:45 p.m. local time) and temperatures dipping below freezing, the Sun Devils fell flat.

Reeling off one big play after another — three scoring plays of 60 yards or longer — Oregon State hit Arizona State with a series of body blows. The Sun Devils have been good finishers this season, finding ways to pull out victories.

Their resolve fluttered this time, the crushing blow an interception of Taylor Kelly that Michael Doctor returned 35 yards for a touchdown. Arizona State's chances in the game and for the playoff ended with a loss of downs on offense.

"We didn't match their intensity and come out how we normally come out," said Kelly, who threw for 264 yards with two touchdowns and two interceptions.

Any chance of playing for the Pac-12 championship now will require help.

The Pac-12 South now has a glut of four teams with two losses. The Sun Devils beat USC, but were blown out by UCLA. The rivalry game against Arizona is Nov. 28 and could loom large in the Pac-12 South race, depending on what happens next weekend.

"We're still playing for a conference championship. We've still got an opportunity to win the South," Graham said. "Win the next two games, I believe we'll be there Dec. 5th. That's all we can do. We can't worry about anything else."