LOS ANGELES | Penn State must recover from its largest deficit of the season to remain undefeated as the Nittany Lions trail USC 20-6 at halftime. Fourth-ranked Penn State gave up a series of big plays in the first half, most notably the longest touchdown scored against the defense this season, and was unable to score any touchdowns during two trips to USC’s red zone.

A look at Penn State-USC at the half.

USC’s big offense

Penn State came into the game ranked second in the Big Ten in explosive play, having allowed just 13 plays of more than 20 yards in four games. USC generated four in the first half alone, three on the ground, inside out on the Nittany Lions’ defense.

Quinten Joyner’s scored from 75 yards on a perfectly called and executed end around, while Woody Marks had runs of 21 and 28 yards to set up Joyner’s second touchdown. As a result, the Big Ten’s No. 2 rushing defense, which had allowed a 100-yard rushing game against its last 16 Big Ten opponents, gave up 147 yards rushing in the first half.

Drew Allar’s second interception

Allar has protected the ball well this season, with just one interception, but his second came from a difficult spot. On a third down in the second quarter, Allar looked from a receiver to his left and threw the right side to Liam Clifford. USC linebacker Desman Stephens II read Allar perfectly and undercut the short ball for the interception. His 42-yard return (Clifford made the tackle) put USC in great field position. But the Nittany Lions got a stop, with a key tackle for loss of cornerback AJ Harris, limiting USC to a 45-yard field goal to take a 17–3 lead.

Two crucial actions of the first quarter

Penn State offensive coordinator Andy Kotelnicki wrote a showbiz attack on the opening series, mixing pace, new formations, Vega Ioane back on the move and a lot of Tyler Warren. It was entertaining to watch, but stuck inside the 5-yard line. The Nittany Lions ran once (a Drew Allar scramble) and had a touchdown pass from Allar to Warren that was called off due to offensive pass interference (receiver Julian Fleming appeared to raise his hands too high).

Penn State’s 3-0 lead after Ryan Barker’s 35-yard field goal didn’t last one play. Joyner blindsided USC’s next play from scrimmage, cutting through several pursuing Penn State defenders to score from 75 yards. It was the longest play Penn State’s defense has allowed this season.

Closing conversations

Penn State’s offense was frustratingly close to two touchdowns in the first half. Warren’s first-half touchdown catch was taken off the board by Fleming’s penalty. And in the second quarter, receiver Trey Wallace had a step on his coverage in the end zone and got his hands on Allar’s pass, but couldn’t complete the catch. On the next play, Allar scrambled looking for Warren, who wanted pass interference. He didn’t get it and Barker made his second field goal of the game.

Warren made a huge impact, catching nine of Allar’s 12 completions for 98 yards. He has 92 yards after contact.

More Penn State football

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USC defensive coordinator D’Anton Lynn faces his alma mater

How Penn State’s passing game has changed this season