Noted defensive innovator Mike Zimmer was asked to bring the heat while roasting Marvin Lewis, the longtime friend, colleague and former boss who gave him free rein to concoct the Double A Gap defense that has spread throughout the NFL the past decade.

“I roasted him,” the Vikings head coach said, “but he roasted me right back.”

Life Learning Center in Cincinnati had chosen Lewis, the Bengals’ head coach, for its St. Patrick’s roast in March. Gallows humor was encouraged, and no subject was off the table between two dear NFL warhorses.

Not Zimmer’s eye surgeries. “He had all kinds of photos with me in my eye patch up on the screen,” Zimmer said.

And not even Lewis’ 0-7 playoff record.

“I think I can tell this story,” Zimmer said with a laugh this week as he prepared to face Lewis and the Bengals for the first time as Vikings coach.

“You know Marvin hadn’t won a playoff game. So I said, ‘So we’re in Minnesota playing the Seahawks in the playoffs.’ I say, ‘It’s 10-9 and we got a 27-yard field goal with 30 seconds left.’ I say, ‘Why is [winning] so hard for Marvin?’ And then Blair Walsh missed the field goal. And I go, ‘Oh. I get it now.’ ”

Zimmer can laugh now. Kind of.

“That night with Marvin was a lot of fun,” Zimmer said. “I had a lot of wine that night.”

Nine months later, it’s a different story. This week, Zimmer took the emotion out of seeing old friends, several players he used to coach and a defense that mirrors his own and is run by Paul Guenther, his former right-hand man in Cincinnati.

“This week,” said Zimmer, “I see numbers, not faces. We just need a win.”

Playing at home as an 11-point favorite, the Vikings (10-3) will clinch their second NFC North title in three seasons if they can dispose of a 5-8 Bengals team that will miss the playoffs for the second straight season.

Origin of Double A Gap

Standing two linebackers in both A gaps — on either side of the center — inches from the football helps apply pressure up the middle, disguise coverages or both, depending on whether one, two or neither linebacker rushes.

“Sometimes, you can feel the stress it causes the offense,” Vikings middle linebacker Eric Kendricks said. “It definitely causes confusion and stuff. And you can get a guy through free sometimes because it comes down to numbers. How many people do they got to block you?”

Or, as Adam Zimmer, Vikings linebackers coach and son of Mike, says, “We’re trying to make the quarterback feel uneasy. … And I think this really messes with them.”

Mike Zimmer said the Double A Gap concept “started a little bit in Dallas [2003-06] with something [Bill] Parcells had that we kind of morphed it into the A gaps.” Then, he said, “we took it to a new level in Cincinnati” from 2008-13.

It wasn’t until after the 2008 season that Zimmer and Guenther, his linebackers coach, really went to work creating the unique and durable Double A Gap wrinkle for what already was an aggressive scheme.

Guenther has talked about countless hours of research and design that went into that offseason. One defense he said they looked at was the one run by the late Jim Johnson in Philadelphia.

From 2009 to 2013, the Bengals had four top-10 defenses. In the 18 seasons just before that, they had one.

“The disappointing thing for me is it was so good — and it still is good — but everybody does it now,” Zimmer said. “They never do it to the extent that we do it, but it used to be like you run the wishbone and no one prepares for it. Now, everybody has their way of taking care of it, whether it’s maximum protection or trying to figure out other ways to attack it.”

Cat and mouse continues

Aaron Rodgers has called Zimmer “an innovator.” When asked to elaborate, he once said, “He’s brought some concepts to the league that other people have tried to copy but not with anywhere near the kind of success he’s had. … He’s done some things that are ahead of his time. I call that an innovator.”

Of course, as offenses have become more familiar with the Double A Gap principles, they’ve discovered better ways to attack it. That’s why you see more shotgun, more quick throws to the perimeter, more receiver screens.

“They start trying to trick you,” Zimmer said. “The [pass] play where they’ll run the tight end to the flat and block the nickel back. That illegal play that they do. We see that almost every week.”

But Zimmer enjoys the game’s ongoing “cat and mouse” tactics.

“The fun part of it is all you can do with [the Double A Gap],” Zimmer said. “And then you got a guy like B-Rob [Brian Robison], who also can drop. Now, you really got three droppers in there possibly. Or three rushers. Or the ends are droppers. You can play man out of it. You can play coverage.”

Zimmer said he sees other teams experimenting with ways to push the envelope even further than he and Guenther have.

“It’s a copycat league, so now on third downs, you’ll see close to 10 guys at the line of scrimmage,” Zimmer said. “Some teams will have one guy in the A gap and one guy in the B gap. Some teams have two guys in the B gaps. I think all that stuff basically started from us.”

In the past three seasons, the Vikings have ranked fifth, sixth and now third in points allowed. Guenther’s defense ranks 13th in points allowed this season, but two years ago, in his second season as Zimmer’s replacement, his defense set the franchise record for fewest points allowed in a 16-game season.

“When you think of [the Vikings’ defense], think of Cincinnati,” Steelers quarterback Ben Roethlisberger said before playing the Vikings in Week 2.

On the radar

The Vikings hired Zimmer on Jan. 15, 2014. But, really, his interview might have started on the third snap of the Vikings’ 42-14 loss at Cincinnati on Dec. 22, 2013.

The Vikings, 4-9-1 at the time, were facing third-and-6 from the Cincinnati 45-yard line when Zimmer shifted into a Double A Gap look with eight defenders at the line of scrimmage.

Seven of them rushed, including one of the A gap linebackers, Vincent Rey. Rey came through the line clean when center John Sullivan turned to block the other linebacker, Vontaze Burfict, who dropped into coverage.

Rey beat running back Toby Gerhart while defensive back Reggie Nelson came in untouched off the right side. The Bengals got the sack, the strip, the fumble recovery and a return down to the Vikings’ 4-yard line.

Two plays later, the Bengals led 7-0.

“I remember we knew pretty much how they were going to protect it,” said Adam Zimmer, the Bengals’ assistant defensive backs coach at the time. “I think [quarterback Matt] Cassel thought he had it picked up. He didn’t.”

Sunday would seem to be a particularly difficult assignment tactically for two teams with the same defense.

“It’s a mental chess game,” Adam Zimmer said, “but I think we got some stuff that will challenge them a little bit.”

Sadly for Mike Zimmer, another loss for Lewis could push him closer to being fired after 15 seasons.

“Marvin is a special person,” Zimmer said. “When my wife [Vikki] died [in 2009], Marvin made me that night come over to his house and spend the night at his house. That’s the kind of person he is. He also came to see me when I was back there during the bye week.”

It also was Lewis who kept encouraging Zimmer as he kept getting passed over for head coaching jobs before finally landing his first one in Minnesota at age 58.

“He was discouraged, but I told him, ‘You know what? It’s not you,’ ” Lewis said. “‘Somebody’s going to make the right decision here, so just keep doing it.’ At times, it can be discouraging, but I encouraged him to continue, and it’s worked out well. They obviously made a great decision, and those that haven’t wish they had.”