He kept thinking about it when they went over plays in practice that didn't work against the Wildcats, but he stayed silent to focus his team on its next opponent: the No. 2 Oregon Ducks.
And he knows many of his players haven't totally moved past it, either -- despite his traditional 24-hour rule that requires to "forget" the previous game after one full day.
"You gotta get over it, but I think we'd be naive to think that the game's completely out of sight and out of mind," Kiffin said. "For those really competitive players, there's still a play in there where they're going to think about it for a long time. That should be natural."
USC lost by three to Arizona, 39-36. Kiffin has lamented the manner of the loss many times since, saying there were a ton of different, small ways the Trojans could have secured a victory.
But having to face Oregon this Saturday has helped him stop thinking about it.
"We all know we screwed up last week," Kiffin said. "We should've won the game. But we're moving forward, and it's good to have a game like this. It's good to have a game to be a big game with a nationally ranked opponent like this, so you don't sit around and keep looking backwards."
Kiffin said Sunday he thought his players were taking this latest loss better than last month's at the hands of Stanford Cardinal.
On Tuesday, quarterback Matt Barkley agreed.
"I think we learned from that Stanford loss how to handle something like that," Barkley said. "We’ve bounced back stronger, I think, and so it’s good for our team, seeing that guys are bouncing back and are ready to go.
"It's not that it didn't affect them the same way. [But] I think there was a little more shock in that first loss because we weren’t expecting it."