Lincoln Riley joked that UCLA quarterback Dorian Thompson-Robinson must have been 15 years old the first time he coached against him, while at Oklahoma.

"Good lord, it's just hard to believe that Kyler [Murray] was playing, which to me just seems like ages ago. I feel like he's been in the NFL forever. Dorian was just starting," Riley recalled this week.

Riley's Sooners hosted the Bruins back in 2018 (a 49-21 Oklahoma win) in Norman, Okla., and then traveled to Pasadena for the rematch of the home-and-home series in 2019 (a 48-14 OU win).

Thompson-Robinson wasn't 15, but he was a true freshman for that first meeting, and now he's a fifth-year senior leading the No. 16-ranked Bruins (8-2, 5-2 Pac-12) against Riley No. 7 Trojans (9-1, 7-1) in the crosstown rivalry game Saturday at the Rose Bowl.

Containing the dual-threat Thompson-Robinson and star running back Zach Charbonnet is the chief challenge in this matchup for USC, which has struggled against the run and especially struggled against scrambling, elusive quarterbacks.

"He was impressive from the jump. He really was. He's a really good player. You could tell he had some real ability at a young age, and I could tell -- we played him twice -- so the second year when we came out here to the Rose Bowl you could tell he had really improved, and it looks like he just continued to improve," Riley said of Thompson-Robinson. "Which, talented player like him and him being coached by the guys that are coaching him, it's not surprise that he has.

"When you watch him you see a guy that's played a lot of ball and played a lot of ball in that system, knows it extremely well, has got good confidence in it, they've got good playmakers around him. So he's obviously had a phenomenal year. It's fun to see -- I've seen kind of the beginning and I'll see a little bit of the end. I'm always a fan of guys that lead and play the game at a high level."

USC defensive coordinator Alex Grinch was with Riley for that second UCLA game and has surely looked at the Bruins' dynamic rushing offense -- ranked No. 8 nationally in averaging 240 yards per game -- and its veteran QB from every angle this week.

"Just extremely efficient. There's so much to like from a quarterback evaluation standpoint -- obviously from a defensive perspective, a lot of frustration when you watch him," Grinch said. "Just very smooth, and very efficient, meaning he's going to take what's there when he needs to. I think that would probably be the biggest growth. ... Taking what's there and having the ability to extend plays with his feet and getting explosive plays with his feet as well. ...

"I think you've got an experience guy that's very confident in what he does. Very hard to shake him."

The Bruins, meanwhile, have an equally daunting matchup with their own struggling defense going against Caleb Williams and Co. They let Jayden de Laura complete 22 of 28 passes for 315 yards, 2 touchdowns and 0 interceptions last week as Arizona stunned UCLA, 34-28.

With so much at stake Saturday for both teams -- but especially the Trojans, who can clinch their spot in the Pac-12 championship game with a win -- let's take a closer look at the Bruins with our own scouting report.

Coach: Chip Kelly (5th season, 26-27)

2022 Record: 8-2 (5-2 Pac-12)

CFP Ranking: No. 16

Scoring Offense: 39.5 PPG (11th nationally)

Scoring Defense: 26.4 PPG (71st)

Total Offense: 504.0 YPG (5th)

Total Defense: 378.8 YPG (69th)

For weeks, it appeared as though USC and UCLA were on a collision course for a top 10 matchup at the end of the season with major Pac-12 championship and playoff implications for both teams.

That possibility slipped away in the waning moments last Saturday as the Bruins wound up falling to unranked Arizona, knocking them down to No. 16 and greatly diminishing their aspirations for a conference title berth. Regardless, UCLA is still alive for the Pac-12 championship if it wins out and receives the necessary help elsewhere in the conference, giving the Bruins every reason to continue playing hard.

This edition of the crosstown rivalry is likely to still be the most meaningful for either team in over a decade, with both squads ranked highly and in pursuit of major postseason goals. The two teams are very similar in makeup, featuring offensive buzzsaws and highly-vulnerable defenses to make this matchup a tough one to predict.

What the Bruins do well:

The Bruins’ offense is legitimately explosive both on the ground and through the air. Dynamic dual-threat QB Dorian Thompson-Robinson has steadily improved in each year of his career and is playing at his best level yet this season. DTR has always had a deep toolkit at his disposal -- a powerful arm, great elusiveness, serious juice as a runner and an inherent confidence in his arm talent to get the ball into tough spaces. His Achilles heel in the past has been his propensity for turning the ball over at inopportune moments, usually resulting from a lack of pocket awareness or rushing his process to miss downfield defenders. However, this year DTR has been much more careful with the football and the results have paid off big for UCLA.

He’s had by far the best year of his career, having thrown for 2,385 yards and 20 touchdowns while completing an eye-catching 71.8% of his passes. He’s only turned the ball over 6 times, with 4 interceptions and 2 fumbles lost. UCLA’s offensive line has kept him relatively clean, allowing just 14 sacks, and the team’s talent at the pass-catching positions has been getting the job done.

Though the receiving corps isn’t stacked with top-level performers, the Bruins have a variety of playmakers able to keep the chains moving. On the ground, however, they are at their most dangerous. Lead running back Zach Charbonnet might be the best runner in the Pac-12 and among the best in the country. He showed that in racking up over 1,300 yards from scrimmage and 13 touchdowns in 2021 after transferring from Michigan. He’s been even better this season, with 1,415 scrimmage yards and 13 touchdowns to show for his efforts despite having missed two games. Thompson-Robinson’s impact on the ground can’t be understated either, as the mobile QB has rushed for 463 yards and 7 scores while averaging 5.5 yards per carry.

The Bruins are running the ball with exceptional efficiency, logging 240 rush yards per game at a clip of 6.2 yards per carry. As a whole, this is a well-rounded offense that primarily relies on dismantling and beating down its opponents on the ground. Thompson-Robinson’s efficiency as a passer and capability as a runner puts defenses in difficult situations when he drops back to throw. So far none of UCLA’s opponents have been able to really hold this offense back over the course of four quarters, even in UCLA's losses.