KJ Costello told the CBS broadcast crew that he’d probably need to throw for 600 yards to beat the defending national champs in Death Valley.

What’s unknown is if that was said with a totally serious face, or if he was joking like his new coach, Mike Leach, is prone to do. What else is unknown is whether Costello knew that no human being had ever thrown for 600 yards in an SEC game, much less against the team with the nation’s longest active winning streak.

Well, until Saturday, that is.

What Costello’s SEC record 623 passing yards did pioneering Leach’s offense was answer roughly 9 months worth of questions in a single afternoon — a stunning, upset-clinching, Air Raid-solidifying, jaw-dropping, welcome-to-the-new-decade single afternoon. A whopping 623 yards of passing with 5 touchdowns sank LSU in a wild 44-34 affair.

In this extended offseason, we heard it start virtually every conversation surrounding MSU.

“How will Leach’s Air Raid translate to the SEC?”

“What will Costello do against faster front sevens?”

“How will they use Kylin Hill?”

Let’s recap that, shall we?

Well, the Air Raid was as advertised all day against an LSU defense who missed All-American cornerback Derek Stingley because of a non-COVID illness … along with nearly every other starter from that national championship team that was inexplicably playing man defense all game. The Air Raid had epic highs, and it helped pull MSU out of epic lows.

Shallow crossing routes, wheel routes, skinny posts, etc. Leach’s offense had it all. Osirus Mitchell, AKA the 3rd-year starter with 1 career 100-yard game, had a game-high 183 receiving yards while JaVonta Payton hauled in 6 catches for 122 yards. Leach kept slinging even when MSU had a 3-point lead with the clock winding down in the 4th quarter. A 24-yard touchdown to an open Mitchell on the right side of the end zone was the Air Raid dagger that Leach dialed up.

Dimes. All. Day.

Costello certainly had his moments when it looked like the game was a bit too fast for him. A missed read on a Jabril Cox pick-6 wasn’t ideal, and neither were the 5 sacks he absorbed. But poised, he was. He hung in the pocket and delivered a 34-yard dart to Payton, he went through his progressions and hit Hill for a long touchdown off a wheel route and above all else, he didn’t wilt when LSU threatened late.

What were the epic lows, you ask?

With MSU leading by 10, Costello had 2 turnovers in roughly 10 minutes of real time — a fumble and an interception — and he nearly coughed it up a third time after the Bulldogs squandered a 10-point lead in a moment’s notice. The thought of “just run the darn ball” had to be on the minds of MSU fans. After all, MSU had the top returning rusher in the SEC in Hill.

Speaking of Hill, remember that question about his usage? Of course you do. You heard it all offseason.

Including the aforementioned wheel route score, he had a whopping 158 receiving yards on 8 catches. He finished the day with 192 scrimmage yards on 15 touches. Um, I think he’ll do just fine in Leach’s offense.

The question after Saturday was more like, well, who’s actually gonna stop Leach’s offense?

In his first SEC game as a head coach, he led the best single-game passing attack in school and conference history. His offense threw for more yards than anyone ever has in Death Valley. And just in case you forgot …

MSU didn’t even have a top-100 passing offense last year.

Goodness.

As someone who was a Joe Moorhead believer and an admitted skeptic of the potential of Leach’s offense in the SEC, I’ll gladly eat crow. Saturday wasn’t just some fluky game in which Leach abandoned the running game and put up a ton of yards. The Air Raid won. It certainly should have won over many folks in this conference.

We’ve never seen an offense like Leach’s in the SEC. In the 2010s, the SEC had 1 offense average 40 pass attempts per game (2016 Ole Miss). In 18 seasons as a head coach Leach’s teams averaged 50-plus pass attempts per game all but 1 season. It was 2006 Texas Tech, who only averaged 49 pass attempts per game.

This is different. Leach is different.

That explains why MSU just earned its 2nd win vs. a top-10 team on the road since 1996. The last time that happened, ironically enough, was Dak Prescott’s historic performance that helped MSU win at LSU in 2014. Since that year, MSU has mostly flirted with SEC mediocrity. Perhaps Saturday was the beginning of the tide turning. Nothing really opposed that optimistic Week 1 outlook.

As Leach’s team celebrated its monumental victory in front of a stunned LSU crowd, Leach conducted a socially distant postgame interview on CBS. Jamie Erdahl asked Leach what it felt like to get a win like that in his SEC return, which was more than 2 decades removed from his days as an offensive coordinator at Kentucky.

“I’ll tell ya. It’s better than average. I’ll tell ya that,” Leach said. “There’s a lot of ghosts in this stadium. We played LSU because New England, Green Bay and the Chiefs had somebody scheduled so we played these guys.”

SEC defenses might not fear Leach’s Air Raid just yet, but Saturday’s showing certainly had to send a chill up their collective spine.