The reasons USC could have lost their first game of the season against Arizona on Saturday night were plenty -- some more familiar than others: A slow start, a lukewarm offense led by a version of Caleb Williams that found more success on the ground than in the air, an inconsistent defense, questionable time management and even a botched field goal that could have given the Trojans the win in regulation but did not. Nearly everything went wrong.

Yet somehow, there was Williams in the third period of overtime, sliding past a Wildcats defender with a stutter step that gave him enough space to sneak into the end zone for the lead. Arizona couldn't match, USC stayed undefeated with a 43-41 win and, afterwards, the reigning Heisman winner felt the need to voice his feelings on a particular hit topic: the Trojans' defense.

"We wouldn't have won that game without the defense," Williams said, jumping to address a question initially directed at Riley. "We were down 17-0. This whole defense thing, our brothers, the score wouldn't be 43-41 without them. Put it simply that way."

Riley echoed the sentiment, noting that an interception in the first half by Jacobe Covington shifted the game while the game-winning tackle for loss on Arizona's two-point try sealed it.

"When you go down 17-0, you get tested internally," Riley said. "Your culture gets tested quick. Defense is what got us going."

Williams and Riley and the rest of the team are aware of the narrative that has been confirmed by both numbers and the eye test: USC's defense is an issue if the Trojans want to play for trophies at the end of the season.

On Saturday, while on the brink of an upset, that defense did just enough to keep the Trojans afloat on a night where Williams could only muster 219 passing yards. Of course, the Heisman winner still found a way to be the game's fulcrum, using his legs to barge his way into the end zone three separate times, including the game winner.

While several of USC's weaknesses were on full display, Riley praised the team's resilience in battling back.

"A lot of teams don't win this game going down 0-17," Riley said.

While in previous games, USC's high powered offense led by Williams has been able to make the defense's inconsistency nearly moot, this one was different. All game long, the Wildcats made it tough for Williams to find open receivers in space, all but nearly erasing his passing and scrambling advantages and turning him into a runner.

"Lanes kept opening up, they kept dropping out and they left me with big lanes," Williams, who ran for 41 yards, said. "I know I haven't ran this year much. Don't really like to run to be honest with you, but you got to do whatever you got to do to win the game."

Williams also expressed multiple times that opposing teams have games against USC "circled" on their calendar, which means they're bound to get their best and can't afford to get off to slow starts.

Riley, for his part, acknowledged the need for improvement while also relishing the fact that USC had once again escaped a tough matchup unscathed.

"My expectations are higher than anybody's." Riley said. "I want to score every fricking time we have the ball. In reality, that's not going to happen. And you can either panic or you can get back on it. We didn't play our best tonight by any stretch, but one game to another, I wouldn't count us out."