Arizona quarterback Khalil Tate, right, is sacked by Southern California safety Isaiah Pola-Mao (21) during the first half of an NCAA college football game Saturday, Oct. 19, 2019, in Los Angeles. (AP Photo/Marcio Jose Sanchez)

LOS ANGELES — Entering Saturday night, nobody was quite sure which Arizona Wildcats team would show up.

Would it be the squad that executed on offense, came up clutch on defense and responded to every challenge at Colorado? Or the one that imploded early and wilted late against Washington?

Unfortunately for Arizona, it turned out to be the latter.

Again plagued by mistakes — many of its own doing — the UA lost to USC 41-14 in front of an announced crowd of 53,826 Saturday night at the Los Angeles Memorial Coliseum.

The defeat was the Wildcats’ second in a row on the heels of a four-game winning streak. They fell to 4-3, 2-2 in the Pac-12. A trip to Stanford looms next Saturday.

Southern California's Damon Johnson, left, recovers a fumble by Arizona's Stanley Berryhill III (86) on a punt during the first half of an NCAA college football game Saturday, Oct. 19, 2019, in Los Angeles. (AP Photo/Marcio Jose Sanchez)

Who will start at quarterback on The Farm wasn’t immediately known after the game.

Freshman Grant Gunnell replaced ineffective senior starter Khalil Tate in the third quarter. Tate never found a rhythm, couldn’t move the offense and again struggled to deal with the blitz.

Gunnell, who started against UCLA on Sept. 28 when Tate was injured, finished the game. Gunnell completed 16 of 26 passes for 196 yards with two touchdowns and one interception.

About a half-hour later, UA coach Kevin Sumlin said no change was in the works.

"There's no quarterback controversy right now," he said. "We’re moving on from this. The depth chart is still the same."

Tate finished 6 of 10 for 47 yards and was sacked six times. For the second week in a row, he finished in the red in rushing yards (minus-27).

It was a disappointing outcome for Tate, who grew up in Los Angeles and played at nearby Junipero Serra High School. He missed last year’s game at UCLA because of injury.

Sumlin said he pulled Tate to try to ignite a stagnant offense.

"It's about the team ... and where we were at that time," Sumlin said. "At that moment in the game, it was time to get a spark."

USC (4-3, 3-1) clearly saw how Washington’s defense attacked Arizona last week and copied that formula. The Trojans blitzed Tate repeatedly. They didn’t let up when Gunnell entered the game either.

Unblocked USC pass rusher Isaiah Pola-Mao drilled Gunnell on his first pass attempt. The ball floated into the arms of Kana’i Mauga for the first interception of Gunnell’s career. It was the Wildcats’ third turnover of the night. They committed four turnovers last week against the Huskies.

Tailback J.J. Taylor, right, was one of Arizona's few bright spots in a lopsided loss at USC.

“The margin for error for us is not that wide,” Sumlin said earlier in the week. “Those are things that in the big picture … we can control and have controlled this year. And for us to be the team that we want to be … we have to get back to controlling those types of things.”

Arizona held USC to a field goal despite the Trojans taking over at the UA 28-yard line. Despite the final score, the defense performed admirably under trying circumstances — repeatedly having to deal with short fields because of an error-prone offense and a shaky punting game. Gunnell’s entrance followed a forced fumble by Tony Fields II that fellow linebacker Colin Schooler recovered.

The dam finally broke late in the third quarter when Kedon Slovis connected with Michael Pittman Jr. for a 54-yard pass to the UA 6. Three plays later, Slovis hit a wide-open Tyler Vaughns in the end zone for a 5-yard TD pass to make it 27-0.

A 55-yard touchdown run by Kenan Christon – USC’s fourth-string tailback – made it 34-0 with 13:13 remaining. Gunnell’s 56-yard TD pass to Brian Casteel on the following series averted the shutout.

In many ways, Saturday’s game resembled the previous two against USC – except Arizona didn’t mount a comeback this time.

Two years ago here, the Wildcats trailed 21-6 at halftime and 28-6 in the third quarter before Tate rallied them to 35-35 tie. Arizona eventually lost 49-35.

Arizona safety Tristan Cooper (31) and cornerback Jace Whittaker (17) break up a pass intended for Southern California wide receiver Amon-Ra St. Brown (8) during the first half of an NCAA college football game Saturday, Oct. 19, 2019, in Los Angeles. (AP Photo/Marcio Jose Sanchez)

Last year in Tucson, the Wildcats trailed by the same score at halftime as Saturday night – 17-0. They were down 24-0 before scoring the final 20 points and forcing USC to recover an onside kick to run out the clock.

The first quarter Saturday felt a lot like the first half from last week. Arizona’s offense and special teams made too many unforced errors, putting its defense in untenable situations.

The first issue arose on USC’s second punt. UA returner Stanley Berryhill III called for a fair catch but couldn’t secure the ball. The fumble set up the Trojans at the 21-yard line.

Southern California's Damon Johnson, left, recovers a fumble by Arizona's Stanley Berryhill III (86) on a punt during the first half of an NCAA college football game Saturday, Oct. 19, 2019, in Los Angeles. (AP Photo/Marcio Jose Sanchez)

As happened repeatedly against Washington, the UA defense held. Chase McGrath’s 31-yard field goal gave USC a 3-0 lead.

Arizona’s third possession ended with another fumble, this one by freshman tailback Michael Wiley. The Trojans took over at the 34, and this time they reached the end zone. Slovis’ 9-yard TD pass to Pittman bumped the USC lead to 10-0 with 23 seconds left in the opening period.

Markese Stepp’s 12-yard touchdown run with 1:02 left in the half increased the Trojans’ advantage to 17 points.

"We talked to the whole team after the game about where we are, what the expectations are," Sumlin said. "That's not going to change. We can't go backwards. That was basically my message to the team.

"How are we going to approach this week? Are you going to let this define you? Or are you gonna keep pushing forward? That's the choice you have. That's the choice that this whole team has."

Extra points

• Arizona defensive tackle Finton Connolly left the game in the first half because of an apparent injury to his right arm. The senior initially got hurt in the first quarter. He tried to come back in the second with a brace on his arm but lasted only two plays.

• Senior right guard Cody Creason didn’t make the trip. Creason, who hadn’t missed a game since he redshirted in 2015, hurt his lower leg/foot in the second half vs. Washington. Redshirt junior Bryson Cain took Creason’s place at right guard. Paiton Fears made his second straight start at left guard.

• Senior defensive back Jace Whittaker made his second career start at safety. With Whittaker shifting inside, freshman Christian Roland-Wallace started at cornerback opposite Lorenzo Burns. Whittaker displaced Christian Young in the starting lineup, but Young played in a dime package in third-and-long situations. Burns got shaken up in the third quarter and did not return.

• Tailbacks Gary Brightwell and Bam Smith, who both sat out last week, were back in uniform. Brightwell played, but only on special teams.

• USC played without multiple starting defenders, including end Christian Rector, linebacker Palaie Gaoteote IV and cornerbacks Greg Johnson and Olaijah Griffin. Safety Talanoa Hufanga, defensive end Drake Jackson and tailbacks Stephen Carr and Markese Stepp all left the game because of injuries.

Contact sports reporter Michael Lev at 573-4148 or mlev@tucson.com. On Twitter @michaeljlev 

Reporter

Michael is an award-winning journalist who has been covering sports professionally since the early '90s. He started at the Star in 2015 after spending 15 years at The Orange County Register. Michael is a graduate of Northwestern University.