Steve Spagnuolo is the definition of a football lifer.

He's been in coaching since 1981, when he took on a job as a graduate assistant at the University of Massachusetts and, since being appointed as a defensive assistant on Andy Reid's original Philadelphia Eagles staff in 1999, he has developed a reputation as an aggressive coach who is not afraid to send the house in order to get results.

Now 24 years on, he is again on coach Reid's staff, having served as the defensive coordinator of the Kansas City Chiefs since 2019. That description perhaps does not paint a completely accurate picture of a coach who is more versatile in his approach than he is given credit for.

Spagnuolo will indeed go on the attack. In the 2022 regular season, only four teams blitzed with six or more pass rushers more frequently than the Chiefs, who did so 6.6 per cent of the time.

But the fact his defense is set to go against the Eagles' offense in Super Bowl LVII is in part a tribute to Spagnuolo's malleability.

The Chiefs were in the top half of the NFL when it came to overall blitz rate in the regular season, but their rate of 26.9 per cent was only enough for 15th in the NFL.

Kansas City sent four pass rushers 70.8 per cent of the time when defending aerial attacks, but they still led the NFL in pressures with 299.

In other words, Spagnuolo's defense can win with the blitz, but it can also succeed frequently getting pressure with just four down linemen, which is critical for every defense in an era where two-high safety coverages that protect against explosive plays have never been more prevalent.

The Chiefs' defense finished the regular season as the eighth-best by yards per play allowed and ranked ninth by Stats Perform's Efficiency Versus Expected (EVE) metric.

It is in the postseason, though, where Spagnuolo's defenses continually come alive.

That was the case in 2007 when his New York Giants defense held the finest offense in New England Patriots history, one that propelled them to an beaten 16-0 regular-season record, to just 14 points in Super Bowl XLII.

His first season with the Chiefs ended in Super Bowl glory as they swarmed Jimmy Garoppolo and the San Francisco 49ers late in the fourth quarter in an underrated aspect of Kansas City's 31-20 comeback win in Super Bowl LIV. In the 2020 postseason, only a Tampa Bay Buccaneers team that ruined the Chiefs' hopes of a repeat at the final hurdle had more pressures than Kansas City's 55.

And this postseason the Chiefs have again risen to the challenge on defense.

The Chiefs have racked up seven sacks in the postseason, second only to the Eagles, and tallied 23 pressures of Cincinnati Bengals quarterback Joe Burrow in the AFC Championship Game, the most crucial being a sack by Chris Jones that gave the ball back to Patrick Mahomes for a game-winning drive in the fourth quarter.

Spagnuolo, though, does not appear interested in taking credit for the continual joy his defenses find in the playoffs, pointing more to the impact of players like Jones than any schematic wizardry.

"I always say this, what you've done in the past or prior games doesn't mean anything going into these games, it's all about our guys stepping up and doing it again," said Spagnuolo on Thursday. 

"Chris Jones, if he's having the game he had last week [in the AFC Championship Game] that certainly helps us, we need our best players to play their best football and I think it comes back to those guys, I think that's why in the big moments we've been able to do that.

"None of that matters now, it's a whole different game and different gameplan, hopefully we can find 60 more minutes of good football."

Speak to the Chiefs' defenders, however, and they won't hesitate to wax lyrical about their coach's prowess for putting them in positions to thrive.

Rookie cornerback Trent McDuffie has enjoyed an excellent rookie season, allowing a combined open percentage across man and zone coverage of 21.54 that is tied for the fourth-best among all corners, according to Stats Perform data.

McDuffie credits Spagnuolo's paternal influence and the varied way in which he uses his defensive backs as key reasons why he has thrived in year one.

McDuffie told Stats Perform: "He's very detailed, which could be tough at times because when you make one little mistake he catches it and it's like 'man yeah I was in the wrong', but he's such a loving dude, he's become such a father figure for me at least, I don't think I could have been here without just the guidance from him and the wisdom he's given me.

"I just love the mentality that our defense is aggressive, we are going to attack the offense, if you're a defensive player knowing you have an offensive gear like 'we're going to go attack the offense', it makes the game much more fun, because you can do so much more. I'm blitzing, I'm playing zone, I'm playing man. He's allowed me to do so much in the defense."

The numbers reflect McDuffie's words. The Chiefs have predominantly dealt in the kind of two-deep safety coverages that have proliferated across the NFL because of the threat posed by their own quarterback, Patrick Mahomes.

Cover 4, Cover 6 and Cover 2 are the coverages in which they have primarily lived, however, they have also played Cover 2 man, where every coverage defender except for the two deep safeties plays man coverage, on 8.92 per cent of pass defense snaps, well above the league average of 2.7 per cent.

Kansas City's defense does often get extremely aggressive when blitzing, playing Cover 1 man, where every coverage defender plays man except for a deep safety, on 25.24 per cent of blitzes, and Cover 0 – where there are no deep defenders – on 18.57 per cent of blitzes.

But there are still a significant amount of zone blitzes mixed in. The Chiefs run quarters (Cover 4) when blitzing 19.52 per cent of the time and Cover 2 on 9.52 per cent of blitzes.

Spagnuolo does look to 'attack the offense', but he takes a multi-faceted approach to doing so, one which consistently pays off in high-leverage situations.

The Chiefs have 27 sacks in the postseason since 2019, 16 of which have come in the second half or overtime, with five in the final two minutes.

Perhaps it is therefore Spagnuolo's timing that is the foundation for the success of his playoff defenses.

Against the Eagles, picking his spots will be crucial.

Aggression will almost certainly need to be tempered given Eagles quarterback Jalen Hurts' aptitude for capitalising on attack-mode defenses through his prowess running the zone-read, the read-option and the run-pass option.

It sets up a fascinating battle between arguably the NFL's most diverse and devastating offense, which consistently makes life easy on its quarterback, and a defense that is significantly more dynamic than many believe and excels at putting quarterbacks in difficult positions in the most important moments.

For Spagnuolo, the challenge is to craft a gameplan that maintains the attacking tendencies of his defense while protecting against the array of dangers Hurts presents.

"There's a lot of responsibility football when you play that kind of offense," Spagnuolo said.

"If we can be good on first and second down to get them in the long third downs, then maybe we can do that [attack], short of that you're always facing the possibility of a run or an RPO on any down and distance, and if you're doing something, you know it could be a big play for you, but it might be a really big play for them."

It's quite the dilemma for Spagnuolo to solve. Fortunately for the Chiefs, history is on the side of him succeeding.