Three years ago, No. 5 Oklahoma traveled to UCLA to face a winless Bruins squad and won handily. While that Bruins loss may be forgotten now, the significance of it shouldn’t go unnoticed. It was the first and only time first-year USC defensive coordinator Alex Grinch squared off against option mastermind Chip Kelly.

Truth be told, Grinch had the dudes up front (several are playing now at the NFL level) to annihilate UCLA’s offensive linemen, many of whom swallowed both the running back and quarterback before the option element even got started.

This time around, the rendezvous between Kelly and Grinch couldn’t be more consequential, with Pac 12 title implications and a shot at a New Year’s Six bid on the line in Pasadena when No. 7 USC meets No. 16 UCLA on Saturday night in what should be an interesting chess match.

Kelly’s offense is, at its core, an option offense, although it’s no longer the traditional zone-read option that we’ve seen from him in the past. The 2022 edition is based more on misdirection concepts to stress perimeter defenders who lack the skill set to match the explosiveness of quarterback Dorian Thompson-Robinson and running back Zach Charbonnet. And though all option offenses are built on attaining a numbers advantage at the point of attack, this season Kelly has been the consummate mathematician in out-leveraging defenses in space.

The Bruins are in the top 10 nationally in rushing yards per game (240) and rushing touchdowns (29). The difference has been in the development of Charbonnet, who at 6 feet 1, 220 pounds, has become an out-of-the-box runner.

Charbonnet is third in the country in yards per rush (6.23) — and he’s averaging 3.1 yards before he even gets touched, per TruMedia. Credit this additional yardage to the play design by Kelly, who will use Charbonnet and DTR to generate explosive plays on the perimeter every week. When the Bruins run, 19.2 percent of their plays have gained 10 or more yards, good for fourth in the country in that category. And they are squaring off against a USC defense that has already surrendered 51 rushes of at least 10 yards.