EUGENE — It's not those loud yellow jerseys causing an optical illusion. Top-ranked Oregon's speedy offense has defenses afraid to blink.

EUGENE — It's not those loud yellow jerseys causing an optical illusion. Top-ranked Oregon's speedy offense has defenses afraid to blink.

As Stanford coach Jim Harbaugh described it, "Oregon is fast-fast."

The undefeated Ducks have hurried past all their opponents this season, but on Saturday night they'll be challenged by No. 24 USC at the Coliseum. While the Trojan defense isn't necessarily shutting down opponents, the team has dedicated its bye week to get ready for Oregon's speed.

"They are so explosive," USC coach Lane Kiffin said. "The style they play is like something we haven't seen. Or probably anybody's ever seen."

Oregon coach Chip Kelly took the spread-option and mutated it, creating what some have dubbed the "blur offense." The team ranks atop the country with an average of 569.1 yards total offense each game. They average 55.1 points per game, also best in the nation.

The Ducks (7-0, 4-0 Pac-10) chewed up 582 yards en route to a 60-13 victory against overwhelmed UCLA last Thursday night. Quarterback Darron Thomas threw for 308 yards and three touchdowns, emphasizing that Oregon's nimble efficiency isn't limited to the ground game.

"We were having a hard time keeping up," Bruins coach Rick Neuheisel said.

Indeed, the speed takes its toll. Oregon has outscored its opponents 156-23 in the second half of its games this season.

At the same time, Oregon ranks 114th when it comes to time of possession, with an average of just 26.28 minutes — meaning the Ducks are extremely skillful.

And it doesn't hurt that running back LaMichael James, currently leading the nation with an average of 161.8 rushing yards a game, freelanced on Oregon's track team in the spring.

James, a Texas state champion in the 100 meters when he was in high school, came in fifth in the event at last season's Pac-10 championships. His backup, Kenjon Barner, also ran for the Ducks.

Another fact to consider: The Ducks have 16 touchdown drives this season of less than 56 seconds.

The Ducks are so determined to speed things up that they've even eliminated traditional play calling. Instead, they use big picture boards flashed from the sideline. That's why during games there will at times be an Oregon player holding up a poster that shows four images, ranging from the Burger King to Shaquille O'Neal to a shamrock. The pictures tell the offense which plays to run.

Kiffin said the Trojans' preparation for the Ducks began in earnest even before USC defeated California 48-14 back on Oct. 16.

The Trojans (5-2, 2-2) needed the attention. Their defense, which lacks depth, is allowing an average of 402.6 yards and 24.3 points per game. The team allowed late game-winning field goals to Washington and Stanford.

Last season then-No. 10 Oregon defeated No. 4-ranked Southern California 47-20, a Halloween game that was dubbed Fright Night at Autzen Stadium. The Ducks rolled up 613 yards against USC during the Trojans' worst loss since the 1997 season.

Oregon went on to claim the Pac-10 championship, ending a seven-year run for the Trojans.

This season, it's almost as if the Ducks are rushing toward the next step — a national championship — every week. The Trojans happen to be next.

"Any team who, I guess, has got their head on straight, knows every week is your national championship. You've got to win that week and if you don't win that week, everything after that or before that means nothing," defensive tackle Brandon Bair said. "This is their bowl game and our bowl game this week."