EUGENE, Ore. — On a chilly night at Autzen Stadium, what might be Pete Carroll's most impressive feat finally came to an inglorious end in front of a delirious record Oregon crowd.

The No. 10-ranked Ducks soundly defeated the No. 4-ranked Trojans 47-20 before 59,592 Saturday night and probably knocked USC out of a BCS bowl bid.

But few fans realized just how significant the loss was by Carroll-era standards. For the first time since his inaugural season, a Carroll-coached team lost by double digits, a record of consistency rival coaches marveled at over the years.

Carroll's only other double-digit loss was to Notre Dame, 26-15, in 2001. But that was a mediocre USC team. Then again, many might argue this is a mediocre USC team based on the past three weeks.

By contrast, Penn State coaching legend Joe Paterno has lost five times by double digits since 2006.

In short, this was the worst loss of Carroll's USC career, and it was not just a loss, it was a disgrace. It pretty much evaporated any chance of going to the Rose Bowl, either on New Year's Day or for the BCS title game.

USC (6-2, 3-2) left Oregon with its defense in tatters and suffered a total meltdown in a game many observers said would determine the Pac-10 champion.

In one respect, the loss was not surprising. USC is 0-4 in its past four visits to the state of Oregon, with two losses to the Ducks and two to Oregon State.

The game was reminiscent in some ways of the Trojans' 24-17 loss here two years ago. But the defense never looked this inept against quarterback Dennis Dixon, who at the time was considered a strong Heisman Trophy candidate.

USC's moniker could change from Tailback U. to Missed Tackle U. based on this performance, which seemed more circa 1999 than 2009 by Trojan standards.

Some soul-searching will take place this week as the Trojans again ponder the problems with their defense. And some questions will need to be directed to Carroll, who also serves as defensive coordinator.

Oregon (7-1, 5-0) already had two 100-yard rushers (quarterback Jeremiah Masoli, tailback LaMichael James) midway through the third quarter.

While USC struggled with passing quarterbacks against Notre Dame and Oregon State, the Trojans could not defend the run or the pass against Oregon. Masoli seemed to do both at will especially on a late drive in the second quarter.

Masoli ran 48 yards on a keeper, gained 13 yards on another play and then threw a 17-yard touchdown pass to wide receiver Jamere Holland (a former USC player) that gave the Ducks a 24-17 halftime advantage.

USC surrendered 251 yards in total offense in the first half, an abominable figure for a defense that held teams to 249 yards in the entire game through the first five contests.

USC quarterback Matt Barkley completed 16 of 22 passes for 138 yards with two touchdowns but his stats would be even better if tight end Blake Ayles did not drop a wide-open pass over the middle after he got behind the defense. Barkley was not blameless, though, as he underthrew a couple passes to open receivers.