LSU’s Brian Kelly and Texas A&M’s Mike Elko are no strangers to each other.

They’re just not used to staring at one another across opposite sidelines.

In some ways they’ll be looking into a mirror when No. 8 LSU (6-1, 2-0 Southeastern Conference) faces Elko’s No. 14 Aggies (6-1, 4-0).

Neither probably could have imagined the upcoming hoopla Saturday when the bright lights come on atop 102,733-seat Kyle Field in College Station, Texas, for the big-game electricity of the weekend’s top national matchup.

Just say it’s a long way from the quite similar paths, bootstraps from the bottom up, they took to Saturday’s game between the last two teams unbeaten in SEC play.

Kelly, of course, is college football’s winningest active coach in a career that began with a dozen years at mighty Grand Valley State.

At least he was the head man all the way up the coaching ladder that took him to Central Michigan, Cincinnati and the big jump to Notre Dame before arriving at LSU.

“It’s like my defensive coordinator path kind of married his head coaching path,” said Elko, 16 years younger than Kelly, who turns 63 on Friday.

Elko, an Ivy League Penn graduate, got his start at Stony Brook and toiled at such off-Broadway assistant coaching stops as Fordham, Richmond, Hofstra, even the U.S. Merchant Marines Academy, before breaking through to Bowling Green.

But it was Kelly who gave Elko his big break when he hired him away from Wake Forest to be Notre Dame’s defensive coordinator in 2017.

“Any time you can hire an Ivy League grad, that makes me smarter,” Kelly said. “So that worked out well for me.”

Elko, too.

“I learned a lot,” Elko recalled. “Ton of respect for him, who he is. Certainly appreciate him giving me the opportunity.”

Kelly said Elko was exactly what he was looking for.

“Mike does a great job with players,” Kelly said. “He’s demeaning without being demeaning. He has a standard of what he expects, but has always been able to build relationships with players.

“He’s done it at a lot of different levels, right? And I’ve always respected those coaches because that’s where I came from, as a Division II head coach. He’s worked his way up.”

But this will be the first time that Kelly, an offensive coach, has matched wits with his defensive-minded former assistant.

“He’s got layers to everything relative to how to play defense,” Kelly said. “He’s seen every coverage, knows every defensive front.”

Elko spent that one 2017 season at Notre Dame — it was the Irish team that beat LSU 31-28 in the Music City Bowl — before taking the same job at Texas A&M.

He spent four years as Jimbo Fisher’s defensive coordinator, then two years in his first head coaching job at Duke, before the Aggies lured him back to replace Fisher.

Elko should know LSU well from the four years he spent as A&M’s defensive coordinator before getting his first head coaching job at Duke in 2022.

The first two tussles his Aggies teams had with LSU his defenses gave up a combined 122 points — both of which probably deserve an asterisk.

In 2018 he had the rare experience of giving up 72 points — and still winning the game — the famous seven-overtime marathon, 74-72.

The next year he gave up 50 points to the Tigers, but that was the Joe Burrow-led eventual national champion LSU team that went scorched-earth on every team it faced. The Aggies’ offense wasn’t much help for the 50-7 final scoreboard.

His defenses fared much better the next two years in a 20-7 Aggies victory in College Station the following year and a close, 27-24 LSU win in 2021 in Baton Rouge.

“Brian’s been a really successful head coach that maybe isn’t huge in the self-promotion business,” Elko said. “He’s the winningest coach in Notre Dame history and I don’t know if that’s something that rolls off everybody’s tongue. But he’s been successful everywhere he’s been.”