USC

For USC’s defense, the takeaway from this game is positive

Khalil Tate
USC defensive end Porter Gustin (45) and defensive back John Lockett scramble for a fumble by Arizona quarterback Khalil Tate in the second quarter.
(Chris Coduto / Getty Images)

Arizona quarterback Khalil Tate flitted into the secondary with a head of steam in the second quarter against USC. This was exactly what the Trojans didn’t want to see: a mobile quarterback 23 yards downfield, heading toward safety Chris Hawkins.

“I knew from earlier in the game, he wasn’t trying to shake DBs,” Hawkins said. “He was trying to run us over.”

Hawkins braced himself, got low and launched. His helmet found the ball. The ball squirted loose, and AdoreeJackson picked it up and returned the fumble to Arizona’s 10-yard line.

It was one of four turnovers USC forced during the game. Iman Marshall was gifted an interception when Tate threw a pass right to him. Connor Murphy fell on a Zach Green fumble. And Ajene Harris ended Arizona’s offensive day by intercepting a pass late.

Those were enough to lift USC’s season turnover differential into the positives. USC had a negative-three margin entering the game, 11th in the Pac-12.

The takeaways are the latest development for a USC defense that improved markedly once it escaped a brutal opening four games. In the previous two games, USC had held Arizona State and Colorado to fewer than 100 yards rushing. The secondary had tightened, too. On Saturday, it allowed just 142 yards passing.

During the previous week of practice, multiple USC defenders said, defensive coordinator Clancy Pendergast had emphasized turnovers.

“It seemed like offensively, we were getting unbelievable field position,” USC Coach Clay Helton said. “I have to credit our defense.”

Smith-Schuster recovers

JuJu Smith-Schuster stretched for a high pass along the sideline in the third quarter Saturday. The ball whooshed above his hands. A cornerback careened into his lower back.

Smith-Schuster said his back had been bothering him for much of the season. The defender, he said, “hit the exact same right spot.”

Smith-Schuster crumpled to the turf, where he stayed for several minutes.

“It locked up, and I couldn’t move,” Smith-Schuster said. “For a good about two minutes, I was stiff and I had trouble breathing. I felt like I had the wind knocked out of me.”

Two teammates helped Smith-Schuster to the bench. He moved stiffly, then walked to the locker room.

X-rays revealed no fractures, and he soon returned to the sideline, although his day was done.

Moving more easily after the game, Smith-Schuster said that he was not seriously injured. Had the game been closer, he said, he might have been able to return for a few plays.

USC’s bye week gives Smith-Schuster extra recovery time, and he said he would be back for USC’s Oct. 27 game against California.

“I’ll be fine,” he said. “I mean, if I can break a bone and come back the following week, I feel like back spasms won’t be any problem.”

Mitchell injured

The outlook was more ominous for receiver Steven Mitchell, who planted his left leg during a punt return and collapsed to the turf without being contacted. He immediately gripped his knee.

He left the game and walked to the bus afterward with his knee in a bulky brace. Helton said Mitchell would have an MRI exam on Sunday.

Boermeester’s boot

Aside from extra points and kickoffs, Matt Boermeester had a quiet afternoon. He was called upon just once for a field-goal attempt — from 54 yards away.

Boermeester displayed a powerful leg. The ball soared well above the crossbar, about halfway up the goalposts, with plenty of distance left. But it clanged off the right post.

Quick hits

Outside the visitors’ locker room at Arizona Stadium is a sign written in urgent font: “WARNING EXCESSIVE HEAT.” Saturday was the Wildcats’ first day game of the season — they avoid such games early in the season to stay out of Tucson’s scorching temperatures. By game time Saturday, the public-address announcer said the temperature on the field, where heat is amplified by the artificial turf, was 137 degrees. … Safety Leon McQuay III left the game with minor groin and hip flexor injuries.

zach.helfand@latimes.com

Follow Zach Helfand on Twitter @zhelfand