EUGENE, Ore. - Southern California understands that slowing down Oregon’s offense is best accomplished by keeping it off the field.

That means stopping the Ducks’ rushing game.

Fifth-ranked Oregon features the country’s third-best rushing offense, and second-best overall offense. No. 9 USC has the nation’s third-ranked defense. The two sides will collide Saturday at Autzen Stadium.

“They run the ball. That’s the main thing we’re going to focus on. ... Stop the run and make them pass,” USC cornerback Terrell Thomas said. “It’s going to come down to everyone doing their job. We’re going to have to execute, no matter what they call.

“That’s our No. 1 goal, that’s our main job, to shut the run down.”

The Trojans (6-1, 3-1 Pac-10) are allowing only 252 yards a game, but they will be tested in a key conference game that ultimately could have national championship implications. The Ducks (6-1, 3-1) average 551 yards a game, but haven’t seen a defense the caliber of Southern Cal.

“They’re unbelievable. They’re a real active D-line up front, and they got the best defense we’ll face in a long time,” Oregon center Max Unger said. “We’ve got our work cut out for us. We’ll pretty much have to play a perfect game. It’s going to be a barn-burner. It’s going to be cool.”

The Ducks, with a speedy spread-option offense, average 46.6 points a game.

Quarterback Dennis Dixon has completed 138 of 199 passes for 1,728 yards and 16 touchdowns with just three interceptions, and he has 416 yards rushing and seven touchdowns this season. As a result, Dixon is averaging 308.2 yards in total offense, 11th-best nationally.

Tailback Jonathan Stewart, who is averaging 134 yards a game, rushed for a career-best 251 yards and two touchdowns in Oregon’s 55-34 victory over Washington last weekend.

“They’re extraordinary,” USC coach Pete Carroll said. “They’re the best offense we’ve seen probably since we’ve been here. Nobody’s even gotten close to slowing them down.”

The Trojans announced Thursday evening after practice that Mark Sanchez would make his third start. John David Booty had thrown in practice but continued to nurse a broken middle finger on this throwing hand.

Special feature Florida faces SEC upset

“Mark’s going to start. John had a great week. We decided this afternoon to go in that direction,” Carroll said. “He (Booty) will be able to go if we need him, it’s just the uncertainty that John feels. Hopefully Mark can make it through the game, we can get a win.”

Sanchez passed for 130 yards and a touchdown but was intercepted twice in a 20-13 victory over Arizona. He improved in last weekend’s 38-0 victory over Notre Dame, throwing for 235 yards and four TDs with no interceptions.

The quarterbacks were not available for comment after Thursday’s practice.

College football Two-man race with Tebow, McFadden

USC has won the last three games against the Ducks, including last year’s 35-10 victory in Los Angeles. The Trojans have won their last two in Eugene.

It is the first time in Autzen Stadium’s 41-year history that two top 10 teams will meet.

“We need this ball game,” Carroll said. “We need to get back into Pac-10 play and do something about our situation that we face with a front-running team and a team that’s really out there.”