Mike Zimmer remembers pretty much everything that was discussed in his marathon eight-hour interview with General Manager Rick Spielman in early 2014, when the Vikings were looking to find a hands-on football man who could not only re-establish a winning culture but also maintain it.

But if Spielman asked him then to lay out his blueprint for shutting down Aaron Rodgers and the mighty Green Bay Packers offense, Zimmer doesn’t recall it.

Sometimes, NFL decision-makers construct teams to combat their division rivals. But Zimmer said his previous employers, the Cincinnati Bengals, were concerned more with building a contender with its own identity than worrying about keeping up with the Baltimore Ravens and Pittsburgh Steelers in the AFC North.

The way Zimmer and the Bengals saw it, with the belief they had in their organizational philosophies, they would construct a powerhouse and force the rest of the division to adapt to them.

“Let’s just get the best players here and let’s go play,” Zimmer recalled this week. “Let us be the better team, that’s what it was all about. And it’s kind of the same way here.”

Spielman and Zimmer found common ground with that mentality. And in the past 22 months, they have worked together to overhaul an outdated defense, using savvy signings and a fistful of versatile and athletic early-round draft picks to inject youth, speed, attitude and creativity into a unit that has quickly became the class of the NFC North and one of the best in the NFL, too.

The Vikings, winners of five straight games, have gotten contributions in all phases while climbing to first place. But Zimmer’s defense, the only one in the league that has allowed fewer than 24 points in every game, is the biggest reason why they are in position to end the Packers’ four-year reign in the division.

“They’ve really done everything right defensively,” said former Philadelphia Eagles and Cleveland Browns front-office head Joe Banner, now an ESPN analyst. “They’ve drafted effectively, they’ve re-signed the right guys and they brought in a free agent here and there to supplement things. And then they coach them really well. So they’re 4-for-4 on that.”

Difficult decisions

One of Zimmer’s first moves after getting hired in January 2014 was to sit down with both the college scouting and pro personnel staffs to outline what he was looking for at each position. Zimmer had a significant role in the scouting process, but he has trusted Spielman and the rest of the front office to give him the type of defenders he covets.

That winter, the Vikings had to make some difficult decisions when it came to their own group of free agents. Eroding cornerstone defensive linemen Kevin Williams and Jared Allen were about to become free agents. So was speed-rushing defensive end Everson Griffen, who was not a full-time starter in his first four seasons but flashed as a reserve.

Moving on from Williams was a no-brainer decision because the Vikings had drafted defensive tackle Sharrif Floyd the previous spring to play his three-technique position. But Allen was coming off his seventh straight season with a double-digit sack total.

The Vikings, after getting debriefed on what Zimmer was looking for at defensive end, concluded that Griffen, an all-around defender, was the one to keep. Allen has 7 ½ sacks in 2014 and 2015 with two teams. Griffen has racked up 17 ½.

“At that time, I didn’t know Everson very well,” Zimmer said. “I knew the talent he had. That was a lot of Rick. You know, a lot of these have been Rick’s decisions. That first year, I was doing so many things to try to get going, I relied on [the front office] a lot.”

Those decisions included signing free-agent nose tackle Linval Joseph and cornerback Captain Munnerlyn. Both Spielman and Zimmer agree that free agency is a gamble, a roll of the dice they would like to avoid. But after underwhelming debut seasons in Minnesota, Joseph and Munnerlyn have been standouts this season. So has reserve defensive tackle Tom Johnson, the former journeyman who has recorded 8 ½ sacks since signing with the Vikings in 2014.

“You can’t have success if you don’t have a front office that brings in players that fit what the coaches want to do,” Banner said. “It seems like they are very much on the same page with what they need defensively.”

The draft: a team’s best friend

Most of the Vikings’ impressive defensive core, though, has come from the draft.

From 2012 to 2015, the Vikings selected nine defenders in the first three rounds. Only the New England Patriots drafted more. The Vikings grabbed five of those defenders in the first round, tied with the New York Jets for the most over that span.

Three of those first-round defenders, safety Harrison Smith, cornerback Xavier Rhodes and Floyd, were selected before Zimmer was hired. But they fit snuggly in his scheme.

In 2014, Zimmer pushed Spielman to draft do-it-all outside linebacker Anthony Barr even though he was a 3-4 pass rusher in college. This past spring, the Vikings drafted cornerback Trae Waynes with the hopes of pairing him with Rhodes for the long haul, but for now he is team’s fourth corner behind Rhodes, Munnerlyn and 2015 newcomer Terence Newman.

And despite the Vikings being stronger on the defensive side of the ball, they also used their next two picks on defense. Second-round pick Eric Kendricks is now starting at middle linebacker, and third-rounder Danielle Hunter is getting snaps at defensive end.

“To be honest, I love their talent,” former NFL safety Matt Bowen said. “They’re very young, they’re very fast, they’re very athletic and they’re very versatile. I think those are the key things you look for in every defensive player in today’s NFL.”

Fourteen of the 25 defenders on the 53-man roster were not here when Zimmer arrived.

Defensive end Brian Robison, outside linebacker Chad Greenway, Smith and Rhodes are the only holdover starters from the end of the era of Leslie Frazier, whose Cover Two scheme asked defenders to sit back in zone coverage and let the play come to them.

“It was important [to acquire a bunch of players through the draft] because the talent we had at the time, we were not as talented as far as what we wanted to do,” Zimmer said. “It was a completely different system that we’re running now.”

The Zimmer effect

When Banner interviewed offensive coordinators for the vacant head-coaching gig in Cleveland, he asked them which defensive guru gave them the most headaches. It wasn’t Bill Belichick or Rex Ryan.

“They always said the Zimmer defense was always the hardest defense to read,” Banner said. “In my opinion, the success of the defense is really a reflection of the coaching. … You could make the case that he’s the top defensive coach in the league.”

In 2013, Frazier’s final season as coach, the Vikings allowed a league-high 30 points per game and ranked 31st in the NFL in yards allowed. Last season, under Zimmer, they leapt to respectability. While they struggled to close out games, they ranked 14th in total defense and seventh against the pass.

In 2015, only the Bengals have allowed fewer points per game. The Vikings rank third in the NFL on third down and are fifth in red-zone defense.

“I think we’re more fundamentally sound,” Zimmer said. “They understand what we’re trying to do, and I think they’re playing a little bit faster.”

And while there is no official statistic for this one, one would guess they rank last in the league when it comes to which defenses opposing quarterbacks want to face on third-and-long, when Zimmer can thumb through his thick playbook of double-A-gap blitzes.

Bowen got giddy when talking about what he saw from the Vikings in last month’s win over the Detroit Lions, when they sacked Matthew Stafford seven times, many of them with unblocked defenders.

“Matthew Stafford had no idea where they were coming from. None,” Bowen said. “He couldn’t figure them out. The Lions couldn’t figure him out.”

Here come the Packers

Even though he tossed five touchdown passes in a pair of wins against the Vikings last season, Rodgers handed out high praise for Zimmer this week.

“Zimmer is an excellent football coach,” he said. “Any time you are in the forefront of revolution in this league, which they do with their seven-[man] and eight-[man]-up looks that they started in Cincinnati, that says a lot about the type of coach you are.”

And even though the Packers have dropped three straight games, leading to criticism being lobbed at Rodgers over in Green Bay, Zimmer said “they look the same to me.”

Bowen mentioned three reasons why he thinks the Packers are struggling offensively. He sees that their receivers aren’t creating much separation against man-to-man coverage. He pointed out that they have gotten away from running the ball. And he says Rodgers’ technique “has broken down a little bit” with him being asked to mask their issues.

“You add all of that up together, and they’re not producing offensively, not like what we’re used to seeing,” Bowen said.

Bowen expects the Vikings to play a lot of press-man coverage Sunday, trying to bump Randall Cobb and the Packers wideouts off their routes. And he thinks Zimmer will be Zimmer, sending pressure in third-and-long situations from a variety of different looks. The Vikings, though, will have to be wary of Rodgers slipping out of the pocket to burn them, something he has done time after time over the years.

The balance of power in this rivalry could be shifting, though, with all the defensive playmakers brought in by Spielman and Co. working as one to execute the plays being called by Zimmer, one of the NFL’s top defensive minds.

The Vikings have constructed a defense that looks ready to finally put up a fight against Rodgers and the Packers, even if they didn’t build this haymaker-throwing unit with these NFC North bullies specifically in mind.