The biggest news coming out of USC's loss to Notre Dame isn't that it ended the Trojans' eight-game winning streak in the rivalry series.

Rather, it is this: It was the Trojans' first regular-season nonconference loss since Sept. 21, 2002 (Kansas State). In fact, during that span, the Trojans' only other loss to a team not from the Pac-10 was to Texas in the 2005 national championship game.

In other words, Pac-10 teams beat the Trojans 15 times? Foes outside the Pac-10: Zero.

That always went a long way toward explaining to, say, SEC supporters why USC was the nation's top program during the Pete Carroll era of college football, and that the quality of the Pac-10 was better than some perceived.

But USC losing to Notre Dame now hurts the Pac-10 in terms of perception for the same reasons (even though the Trojans were playing without starting QB Matt Barkley; the Irish also were playing their No. 2 QB).

The Pac-10 has leaned on its depth this year to justify many of the conference's mediocre records. That and being 10-5 versus other BCS conferences.

But the Trojans losing at home to a mediocre Notre Dame team hurts the résumé. As in: Didn't Arizona lose at home to USC just two weeks ago? So by the transitive property of college football, Notre Dame is now greater than the Wildcats (a laughably inexact way to measure things, but it's all we have without head-to-head).

Of course, the Pac-10 winning two BCS bowl games would sort of make the Trojans' slip less notable at season's end.