This thing that almost didn’t happen was the perfect match all along.

Mike Leach wanted Rocky Long. He got Zach Arnett — and now both are on the verge developing a special season at Mississippi State that would certify Leach’s move to the big, bad SEC, and land Arnett a Power 5 head coaching job in the process.

All because Long turned down Leach’s offer to be his defensive coordinator — and told Leach he’d be crazy to not hire Arnett, his 33-year-old DC at San Diego State.

“Zach has done just a terrific job,” Leach says, and if you know Leach, those words aren’t easy to say about any defensive coordinator, much less his own.

But this thing was cosmic destiny of sorts, a fitting connection for the coach who loves a good conspiracy and ghost story, and believes beyond the shadow of a doubt in the unique powers of the universe. That’s right, the universe.

Leach waited for years to coach in the SEC. He nearly got the Tennessee job 3 years earlier, when the athletic director offered him the job and the university president said no because the former beloved coach was spearheading a coup … and we don’t need to rehash that nonsense.

Leach wanted in the SEC, so you better believe he wanted everything set up at Mississippi State to make it work. His first call was to Long, arguably the most respected defensive coach in college football this side of Nick Saban.

Long had just retired at San Diego State after winning 81 games in 9 seasons, but he wasn’t done coaching. So Leach called and asked Long to come help him make some noise in the SEC.

Long declined but told Leach to hire Arnett, a defensive wunderkind and former player and pupil of Long. Arnett had never been away from Long, as a player at New Mexico, and a graduate assistant, assistant coach and DC at San Diego State.

And now Long was telling Leach, who was getting ready to jump into the bubbling tarpit that is the SEC, that Arnett was the best guy for the job.

“I’d never be here without (Long),” Arnett said.

Then again, think about what Arnett leaped into, blindly: He never coached defenses for a team whose offensive philosophy wasn’t based on ball control and field position. Arnett left that security for Leach’s philosophy of ignoring down and distance, and 4th-down conversions as a viable option anywhere on the field.

The year before Arnett arrived, Mississippi State gave up 29 points per game. The Bulldogs give up 22 now.

The year before Arnett arrived, Mississippi State gave up 400 yards per game. The Bulldogs give up 333 now.

The year before Arnett arrived, Mississippi State gave up 40 percent of 3rd-down conversion. The Bulldogs give up 29 now.

Those are tangible numbers that can’t be ignored, and they’re particularly impressive against the backdrop of Leach’s play-calling whims (the good and the bad) and the reality that Starkville isn’t the easiest place to recruit elite 4- and 5-star defensive players.

Arnett is doing this heavy lifting with mostly 3- and some 4-star players who are developed into legit SEC stars.

Guys like linebackers Nathaniel Watson and Jett Johnson, cornerback Emmanuel Forbes and safety Jalen Green. All among SEC statistical leaders, only 1 a top-200 recruit.

“In this business, there are no excuses,” Arnett said. “At the end of the game, there’s a winner and a loser. When we got here, I told our guys that win, lose or draw, you’re going to know you got into a fistfight every time you play us.”

Arnett’s unique 3-3-5 defense — the same defense Long used in dominating the Mountain West for so long — has been the perfect complement to Leach’s Air Raid offense. More to the point: Arnett’s defense hasn’t been deterred by Leach’s offensive style and quick 3-and-outs.

They just keep coming, aggressively stressing offenses on multiple levels. Up next: Arkansas, in a critical West Division game, with both teams trying to keep pace with Alabama.

“There’s no fear in him,” Arkansas coach Sam Pittman said of Arnett.

When Long was selling Arnett to Leach, he said one thing that immediately grabbed Leach.

“All great competitors are never satisfied,” Long told Leach, explaining that Arnett is obsessed with the importance of the little things no matter how good things look.

This, of course, is the foundation of Leach’s Air Raid offense. There’s nothing complicated about it — but every play can always be better, no matter how many points you’re scoring.

It’s 7 to 10 plays run from about 70 formations, and run so well — to the exact step and throw and timing — that if the play is blocked well enough and run the way it should, Leach believes it can’t be stopped.

Want to know why Leach attempts so many 4th-down conversions? (Or used to, anyway. He’s actually been more conservative since coming to the SEC.) Because, sonofagun, if it’s blocked right and run to the exact step and throw, you’re not stopping it.

And if they don’t convert? Well, welcome to running a defense for Mike Leach.

“Change is constant,” Arnett said. “Quit complaining about a reason why it’s not what you think it should be, and find a way to get it done.”

There’s your cosmic destiny. And maybe even a special season.