His arrival last December, in the midst of the darkest defensive stretch in school history, was hailed as a potential program-saving moment at USC. At UCLA, where he revived a struggling defense in a single season, his departure was viewed as a disastrous setback, only made worse by the destination.

But almost a full year after defensive coordinator D’Anton Lynn traded one side of the crosstown rivalry for the other, reality seems to have settled somewhere in the middle. USC, at 5-5, didn’t suddenly field one of college football’s best defenses with Lynn at the helm. Nor have the Bruins, at 4-6, bottomed out without him, as first-year coordinator Ikaika Malloe has kept UCLA’s defense afloat just fine.

As Lynn returns to the Rose Bowl this week, on the other sideline this time, both schools seem pretty satisfied with where they stand on defense.

“He’s done a tremendous job at this point,” USC coach Lincoln Riley said of Lynn.

“We had complete confidence,” UCLA’s DeShaun Foster said of Malloe. “This isn’t anything shocking to us about how the defense is playing.”

It wasn’t long after the two rivals faced off last November that Riley zeroed in on Lynn as the focus of his coordinator search. He’d made a compelling case in UCLA’s 38-20 win over USC, having held the Trojans to three rushing yards, the fewest ever from a Riley-led offense. It was a fitting finish to a tremendous debut season in which Lynn transformed a mediocre UCLA defense into one of the nation’s best in a matter of months, a unit that gave up 11 fewer points and 102 fewer yards per game than the year before.

Two weeks later, USC stole Lynn away with one of the biggest contracts ever for a college defensive coordinator. UCLA made its own push to keep him, but former coach Chip Kelly said the Bruins “weren’t in the ballpark from that standpoint.”

It was a significant swing from Riley, who was desperate to iron out the issues that followed him since his days at Oklahoma, where his dedication to defense had been regularly questioned. By the start of his third season at USC, Riley tried to change that tune. Everything, he said in February, would be done “with a defensive mind first.”

“They are passionate about playing elite defense here at SC by any means necessary,” Lynn said.

Meanwhile, the plan at UCLA in light of Lynn’s departure was to not disrupt a defense that already was on an elite path. So after a strong showing in the LA Bowl, Kelly promoted from within, making Malloe, the defensive line coach, his full-time coordinator. When Kelly left for Ohio State in February and Foster took over, he kept Malloe in place.

Malloe kept the scheme largely the same. But maintaining the progress made by Lynn the previous season was made all the more difficult by the fact that UCLA’s defense had been depleted by the NFL draft. The pass rush especially had been picked apart. Others, like standout safety Kamari Ramsey, followed Lynn to USC.

The path since, for both defenses, hasn’t always been linear. Early progress at USC was hampered when it lost arguably the two best players on its defensive front, Eric Gentry and Anthony Lucas, for the season, leaving it dangerously thin on depth, while UCLA struggled through a 1-3 start in which it gave up more than 30 points per game. Neither team has had much luck rushing the passer, either, with USC ranked 111th and UCLA 79th in sacks.

But as the one-year anniversary of Lynn’s departure nears, both schools are undoubtedly on different tracks than they were for their last meeting.

It’s not difficult to quantify that impact at USC, where Lynn has — statistically, at least — lived up to his high billing. USC has gone from 121st in the nation in points given up last season (34.4 per game) to a respectable 42nd (22). The run defense leaped from 119th (186.5 yards per game) to 52nd (132). Missed tackles are down considerably — from nearly 11 per game to an average of eight, and explosive plays have plummeted, as USC went from 124th in 20-plus-yard plays given up to 13th this season.

“Certainly, the progress is real by stats,” Riley said. “But you can just feel the difference right now.”

It’s on the most critical downs where that difference has been felt most at USC — and missed most at UCLA.

On third downs, USC’s defense ranks 22nd in opponent conversion rate (32.6%), down from 109th last year (43.6%), while UCLA fell from 35th (35.5%) with Lynn all way to dead last in college football without him, the only team this season to have opposing offenses convert better than 50% of the time.

USC defensive coordinator D’Anton Lynn walks on the field during a win over Louisiana State in Las Vegas on Sept. 1.

(Jevone Moore / Icon Sportswire via Getty Images)

The same trend bears out in the red zone, where UCLA was the best defense in college football last season at limiting touchdowns. Just 35% of red zone trips under Lynn ended in touchdowns, while 75% of those trips have ended in touchdowns this year. At USC, 69% of red zone trips resulted in touchdowns a year ago, compared to 51% now.

“You can look at the stats and see a pretty massive difference there,” Riley said. “But I don’t think that tells the whole story. I think D’Anton’s been a really consistent leader.”

Nor do stats quite illuminate exactly what Malloe has meant to UCLA’s defense, which was left with mostly spare parts when he took over.

UCLA is giving up nine more points and 45 more yards per game than it did last year under Lynn. But over their past six games, the Bruins actually have given up fewer yards (311) and points (24.6) per game than Lynn’s USC defense over the same span (404 yards, 25.3 points).

“The job Malloe’s done, he’s been able to maximize the whole defense’s potential, putting everybody in spots to make plays,” linebacker Carson Schwesinger said, “so a lot of our success could be attributed to the work that he’s put in.”

Success is ultimately a matter of perspective. But for the man at the center of the conversation, there will be no added meaning Saturday when his old team clashes with his new one. Asked about his return to the Rose Bowl, the unassuming Lynn said only that it was “exciting” and “another big game for our guys.”

He shrugged off any other significance.

“It’s ball at the end of the day,” Lynn said.

But the significance of Lynn’s decision last November isn’t lost on Riley, whose defense has been the steadiest part of the Trojans’ rocky season.

“He’s done everything that we would’ve asked,” Riley said of Lynn. “The culture defensively within our program has really shifted in a lot of ways.”