EUGENE, Ore. -- Jonathan Stewart rushed for 168 yards and two touchdowns before hurting his ankle, and No. 21 Oregon defeated Pac-10 rival Stanford 48-10 on Saturday.

Dennis Dixon threw for a score and ran for another for the Ducks in the rare conference matchup to open the season.

Dixon, who has the starting job all to himself after rotating with Brady Leaf last year, completed 21 of 30 passes for 236 yards as temperatures at Autzen Stadium zoomed into the 90s.

Stewart, a sophomore, injured his right ankle late in the third quarter. He walked off the field unaided but did not return to the game. The team reported a "slight" ankle sprain.

Stanford's Trent Edwards completed 20 of 34 passes for 224 yards and a touchdown. Mark Bradford had nine catches for 108 yards.

Stewart burrowed in from a yard out to make it 10-3 for the Ducks early in the second quarter. Dixon's 15-yard scoring pass to Jaison Williams upped the lead.

Stanford answered with Edwards' 26-yard TD pass to Bradford.

Stewart scored again on a 3-yard run and Paul Martinez added a 24-yard field goal to make it 27-10 at halftime.

Dixon's 2-yard keeper put Oregon up 34-10 midway through the third quarter.

Aaron Zagory missed a 32-yard field goal attempt that would have narrowed it, before the Ducks scored on Jeremiah Johnson's 2-yard run.

Oregon blocked Zagory's 37-yard field goal attempt in the fourth quarter and it was scooped up by linebacker A.J. Tutele, who ran it back 72 yards for the score.

The game was originally scheduled for October, but the Pacific-10 Conference instituted a full round-robin conference schedule, forcing Stanford to chose between 12 straight games or the opener at Oregon.

Later, the Big Game against California was rescheduled for Dec. 2, giving the Cardinal a late bye.

Oregon had not opened against a conference opponent since 1997. Stanford opened against Washington State in 2000.

Oregon finished 10-2 last season, its best record since 2001. The Ducks were second in the Pac-10 behind Southern California with a 7-1 mark and suffered their only regular season loss to the Trojans. The Ducks lost 17-14 to Oklahoma in the Holiday Bowl.

Oregon got a big game on defense from the player replacing All-American defensive tackle Haloti Ngata.

Juco transfer Jeremy Gibbs recorded a sack, a blocked kick and caused a fumble.

The Cardinal, coming off their fourth straight losing season, are 43-26-1 in the all-time series with Oregon, but the Ducks have won the last five games, including a 44-20 victory last season.

The crowd at Autzen on Saturday numbered 58,450, a record for an opener and the fourth-biggest attendance ever.