The game started off with the Trojans clearly on top, and it didn't change much by the end.
The Irish quickly fall to 21-3 as USC scores on its first few drives.
Notre Dame was able to force several turnovers, but couldn't complete on most of those drives.
Irish head coach Charlie Weis said, "The bottom line is we never got into a flow between the offense and defense in the game."
"When the defense got a play to get off the field, the offense wouldn't put it in."
The Blue and Gold managed to keep the game within two touchdowns and was still in the game until the fourth quarter.
Players and Weis agreed the game could have gone in their favor if they had been able to execute when they needed to.
The loss is tough for the seniors especially because it's now the fourth time they have lost to the Trojans, including last year's heartbreaking last second defeat.
The team now looks to see where they will finish in the BCS rankings when those come out Sunday afternoon.
That will help decide which bowl game they'll be headed to in the next six weeks.
For more on the game including video from Los Angeles, check out our sports page.