Another inconsistent defense threatens to ground No. 9 USC's loftiest ambitions

LOS ANGELES (AP) — Southern California scored a combined 90 points in back-to-back road victories over the past two weeks.

The No. 9 Trojans also fell four spots in the AP Top 25 during that stretch.

That's because the college football world knows USC's defense has been leaky and inconsistent again under second-year head coach Lincoln Riley and his longtime defensive coordinator, Alex Grinch. Despite another year of talent additions and familiarity with the scheme, the Trojans are still struggling to stop anybody for an entire game, and it's draining the momentum from the national title aspirations at USC (5-0, 3-0 Pac-12).

Riley and Grinch are still emphasizing the positives of USC's unbeaten start, but the coaches realize that even an offense as impressive as Caleb Williams' group probably can't carry an unsuccessful defense anywhere special.

“We’re not immune to struggle just because the logo says SC,” Grinch said Tuesday night after the Trojans began preparations to face Arizona this weekend. “We’ve got to embrace it. And man oh man, it’d be fun to get on the other side of it. We’re fighting and scratching and clawing, not hiding under a desk, and we’re excited for next week.”

The Trojans fell from No. 5 to No. 9 despite winning at Arizona State and Colorado. USC held double-digit leads in the fourth quarter of both games, but ultimately had to hang on through uncomfortably tight finishes.

“There’s 40 minutes of elite football, winning football,” Grinch said. “We’ve got to coach them through that next 20, and get 60 out of them. You take it very personal as a coach. That’s the only way you can get better.”

Grinch has been Riley’s defensive coordinator for the past five seasons at Oklahoma and USC. The Trojans' plummet in the polls is reflective of the national narrative about Riley’s teams even before he moved from Norman to Los Angeles: They’ve frequently been offensive juggernauts restrained by defenses that can’t hang with the best opponents.

This offense ranks among Riley's finest so far. USC is the nation’s highest-scoring team at 56.0 points per game, and Williams has been just as good as he was last season while winning the Heisman Trophy, completing 74.5% of his passes for 1,603 yards and 21 touchdowns with just one interception.

But the Trojans' defense is an embarrassing 98th in the FBS with 404.4 yards allowed per game. Only Stanford and Colorado have been worse defensively among Pac-12 teams, and that’s largely because USC’s offense racked up a combined 1,071 yards in its victories over them.

The Trojans have allowed 24.2 points per game, good for 62nd in the FBS. Three teams have already scored at least 28 points against USC — and the Trojans' schedule only gets worse.

After they host the up-and-coming Wildcats, USC begins a brutal second half: No. 10 Notre Dame, No. 18 Utah, California, No. 7 Washington, No. 8 Oregon and UCLA — all without a bye week.

Riley insists the Trojans have improved on defense this season, citing a superior pass rush and a stronger defensive front. The Trojans are indeed getting to quarterbacks more frequently, and their coach believes they’re tougher against the run.

“We’re a little bigger, thicker, stronger inside,” Riley said. “When things have popped this year, when we’ve given up a run, it doesn’t look the same. It’s not because people have just got moved off the ball. It’s just a sturdier front overall. ... We’ve played some stretches of ball this year that, frankly, I don’t know if we were capable of last year.”

Before Grinch joined Riley, he coordinated defenses for Mike Leach and Urban Meyer. So while his coaching pedigree is strong, his results haven’t been great. Sooners fans had grown weary of their team's propensity to get shredded on the sport's biggest stages even before Riley and Grinch left for the West Coast, where their first Trojans team allowed a whopping 415.1 yards per game.

Seven of the Trojans’ final eight opponents last season scored at least 27 points. USC gave up a combined 93 points in its season-ending losses to Utah in the Pac-12 title game and to Tulane — which averaged more than 10 yards per play — in the Cotton Bowl.

If this defense looks bad now, it would appear to be even more overmatched next season when the Trojans move to the Big Ten with its array of dominant defensive programs. Riley and Grinch are pushing ahead and trying to fix the little things that have added up to big disappointments this season.

“Finish tackles on the perimeter and keep the quarterback in the pocket,” Riley said. “When we did that, we played high, high-level defense. When we didn’t do that, like most defenses, you’re going to get exposed. ... There was a few times when we were just undisciplined, and you can’t let guys get outside the pocket, especially the quality quarterbacks we’re going to see the rest of the way.”

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AP college football: https://apnews.com/hub/college-football and https://apnews.com/hub/ap-top-25-college-football-poll