EUGENE — It became clear that LaMichael James was not too badly hurt when he and Oregon teammate Kenjon Barner danced on the sidelines before the start of the fourth quarter.

The junior duo bopped to “Shout!” with the rest of the sellout crowd at Autzen Stadium as the Ducks cruised to a 49-21 victory over Oregon State in the Civil War rivalry game to clinch the Pac-12 North Division title and a spot in the league’s first championship game.

Earlier in the quarter, James — who ran for 142 yards and the game’s first touchdown — left with an injured left elbow.

“It’s good,” he said, vigorously flexing his elbow after the game. “I could’ve played.”

The demonstration was assurance that he would be ready come Friday night when Oregon (10-2, 8-1 Pac-12) hosts UCLA with a chance to win a third straight conference title and a spot in the Rose Bowl.

Quarterback Darron Thomas, who passed for 305 yards and four touchdowns, said a victory in the Civil War was one of the goals Oregon set at the start of the season. The Ducks (No. 9 AP, No. 10 BCS) have won the past four in the 115-game history of the rivalry.

“This was a big game for the team and we wanted to win it for Eugene,” Thomas said. “The win wasn’t just for us, it was for the fans.”

For the second season in a row, the Beavers (3-9, 3-6) are not going to a bowl game.

James, a Heisman Trophy finalist last season, entered Saturday’s game as the nation’s top rusher with an average of 142.78 yards per game. He was hurt midway through the third quarter when he was hit by Oregon State linebacker Tony Wilson and landed awkwardly on his left elbow.

The junior running back was already wearing a brace on his right elbow, which he dislocated on Oct. 6 against California. He missed two games because of that injury.

Oregon looked as if it was making a strong bid for a spot in the BCS Championship Game until last weekend, when the Ducks fell to Southern California 38-35. But they bounced back easily against Oregon State.

Versatile Oregon freshman De’Anthony Thomas rushed for 71 yards and had 10 catches for 86 yards and a score. Barner ran for 64 yards and a touchdown, and he also caught a scoring pass.

“I feel like we played real well,” said De’Anthony Thomas, who finished with 197 all-purpose yards. “I can’t wait to play next week. We’re gonna play even better.”

Redshirt freshman Sean Mannion passed for 299 yards and three touchdowns for the Beavers. But Oregon State struggled on the ground with just 16 yards rushing, compared with Oregon’s 365.

James scored early on a 1-yard run, becoming Oregon’s all-time leading scorer with 324 points.

The Beavers tied it 7-7 when Jovan Stevenson grabbed a swing pass from Mannion and weaved his way downfield for a touchdown early in the second quarter.

“You get to play in a rivalry and after the first play, it’s just playing football,” Mannion said. “That’s all there is to it.”

Before the half, Oregon scored on Darron Thomas’ 16-yard pass to David Paulson and his 8-yard pass to De’Anthony Thomas.

Darron Thomas hit Barner for another 16-yard touchdown just before halftime to make it 28-7. Barner ran a yard for another score in the third quarter, and Thomas connected with freshman Colt Lyerla for a 39-yard touchdown early in the fourth period.

Mannion threw touchdown passes in the fourth quarter to Kevin Cummings (19 yards) and Brandin Cooks (23 yards).

Oregon State flanker James Rodgers did not suit up because of a left ankle injury. It was to be the final game of a college career with some great moments and a severe injury.

In the 2007 Civil War, Rodgers scored on a fly sweep in overtime to give the Beavers a 38-31 victory at Autzen Stadium. Oregon State has not defeated their in-state rival since then.

Rodgers was a fifth-year senior this season coming off a pair of knee operations.

Oregon linebacker Dewitt Stuckey (shoulder) and end Dion Jordan (ankle) both played against Oregon State after leaving with injuries against USC.

Last weekend’s loss to USC at Autzen Stadium snapped a 21-game winning streak at home and a 19-game win streak in conference games for Oregon. The Ducks have not lost two straight at home since 2002.

“I felt like we shouldn’t have lost that game,” De’Anthony Thomas said. “But those things happen. Now we gotta get back and win the Pac-12 championship.”

The Civil War, by the numbers

A look at some of the numbers during Saturday’s Oregon-Oregon State game:

62: Number of rushing attempts by Oregon. Oregon State had about one-third of that number, with 21 running plays. The Ducks ran 102 plays.

38: Number of first downs in the game by Oregon. Oregon State had just 15, and only three in the first half.

9: Number of players who had at least one reception for Oregon State. Brandin Cooks and Joe Halahuni led the Beavers with five each.

4: Number of consecutive wins in the Civil War series for Oregon.