CORVALLIS, Ore. -- Fourth-ranked Stanford was wary of Oregon State, and a slow start against the Beavers on Saturday gave the Cardinal even more reason for concern.
After a thrilling triple-overtime victory against USC and the big Pac-12 North contest looming against Oregon (No. 8 BCS, No. 6 AP) next weekend, the lowly Beavers mounted a threat when they closed to within 17-13 in the third quarter.
But then Stanford did what Stanford does, pulling away for a 38-13 victory on Saturday.
"I think we have a mature football team," Cardinal quarterback Andrew Luck said. "We understood it could be a trap game sandwiched between two great teams but I think our football team is mature enough to understand that if we don't win this game the rest of the games don't matter."
Luck shook off the rain and the chill to throw for 206 yards and three touchdowns in the victory.
But it came at a price for Stanford, who lost senior receiver Chris Owusu to a concussion in the second quarter after a helmet-to-helmet collision with Beavers cornerback Jordan Poyer. Owusu was taken from the field by ambulance.
Stanford (9-0, 7-0 Pac-12) extended the nation's longest winning streak to 17 games. The Cardinal have not opened 9-0 since 1952.
Redshirt freshman Sean Mannion threw for 252 yards and a touchdown for Oregon State (2-7, 2-4), which is guaranteed a losing season with the defeat. The Beavers' only wins have come against Arizona and Washington State.
Stanford was coming off the 56-48 overtime win over Southern California. Next week, the Cardinal host the Ducks in a game that could decide the Pac-12 North's representative in the league's inaugural championship game.
Luck completed 20 of 30 passes with one interception. He upped his touchdown pass total to 26, six shy of his own school record set last year, by spreading it around and connecting for scores with Coby Fleener, Stepfan Taylor and Griff Whalen.
Saturday's victory was the Heisman Trophy candidate's first in the state of Oregon.
"I though we left a lot of plays out there," Luck said. "Credit to Oregon State, which played tough. It was a tough atmosphere out there."
The Cardinal opened with a 2-yard touchdown run by Jeremy Stewart before Luck found Whalen with a 17-yard scoring pass to make it 14-0.
Oregon State was efficient on a drive that ended with Mannion's 15-yard TD pass to James Rodgers midway through the second quarter.
On Stanford's next series, Poyer collided helmet-to-helmet with Owusu. As he was loaded into the ambulance, the receiver gave a thumbs up.
The hit knocked the ball out of Owusu's hands and Poyer scooped it up and ran back into the end zone. But it was nullified when Poyer was called for a personal foul on the hit.
Poyer said later he thought he hit shoulder to helmet. But he understood the call.
"It was a bang-bang play. The ref saw helmet-to-helmet contact. He's going to make that call every time," Poyer said.
Erik Whitaker added a 31-yard field goal for Stanford before halftime to make it 17-7.
The Beavers narrowed it early in the second half on freshman Malcolm Agnew's 2-yard scoring dive. It appeared that they had momentum, but on their next series the Beavers were hurt by a holding penalty on Markus Wheaton on a play that would have been good for a first down in Stanford territory.
"We had a pretty nice-looking drive up to that point, I think," Riley said.
Stanford went up 23-13 on Luck's 27-yard touchdown pass to Taylor and before the third quarter was over, Luck found Fleener with a 14-yard pass. Tyler Gaffney ran 10 yards for Stanford's final score.
Overall the Cardinal rushed for 300 yards, compared to just 33 rushing yards for the Beavers. Stanford had 507 yards in total offense, while Oregon State had 285.
"It really hurts you in a game when you can't sustain more running yardage than that," Riley said.
Stanford said Owusu was conscious and had full range of mobility in his extremities. He was taken to the hospital for X-rays.
Last week in the 56-48 victory over the Trojans, safety T.J. McDonald leveled Owusu with a hit to the head, drawing a personal foul penalty late in regulation. The Pac-12 suspended McDonald for the first half of Friday's night game at Colorado for the late hit.
Tests after the game did not show a concussion, but Owusu did strain his shoulder.
Owusu also suffered what Stanford coach David Shaw described as a "minor concussion" in a win at Washington State in mid-October.
Going into the game, the senior receiver had 33 catches for 370 yards and two touchdowns this season. He had a 33-yard run against the Beavers in the first quarter.
Owusu returned to Reser Stadium and was in the locker room after the game. His status for next week against Oregon is not known.