Film review: Chiefs’ third-down defense has become one of NFL’s best

“From the 20-yard line, it’s third down.”

Those last three words can pump adrenaline directly into the veins of Kansas City Chiefs’ fans when said over the loudspeakers during a defensive possession at Arrowhead Stadium; at least, that’s what happens to me.

Those moments are more fun when the defense gets off the field at the end of the play — and that has been the case more often than not for the Chiefs during this five-game win streak. Since Week 8, they have led the league in third-down conversion rate allowed with an outrageous number of 25.8%. That continued in the 22-9 win over the Denver Broncos, where they only allowed four conversions on 14 attempts.

There’s a variety of ways the Chiefs are getting it done when it matters most:

Aggressive play-calling

Defensive coordinator Steve Spagnuolo’s strategy on these particular plays has made him the catalyst for the incredible performances — and that was prevalent from Denver’s first third-down attempt of the game.

Like a typical third-and-short, the Chiefs show press-man coverage; they seemingly want to use safeties Tyrann Mathieu and Juan Thornhill in deep-half coverage roles, while linebacker Anthony Hitchens takes the running back.

However, that changes at the snap; suddenly, slot cornerback L’Jarius Sneed is flying into the backfield while linebacker Willie Gay Jr. comes from the opposite edge. On top of that, Hitchens throws himself into the pocket after he sees the running back commit to pass protection. The chaos caused to Denver’s pass protection ends in a sack by edge rusher Melvin Ingram.

This all-out effort was a cover-zero blitz; the zero indicates no deep defender over the top of routes, which happens when Mathieu and Thornhill slide down to cover the receivers left by Sneed and Gay. The idea is that the pass rush will outman the pass protection seven to six, leading to either a sack or enough pressure to force an incompletion before the vulnerable aspects of that coverage can be taken advantage of.

The intelligent defenders know how to utilize that heavy pressure to make plays. If you watch Mathieu’s coverage on the tight end, he anticipates a quick pass and jumps in front of the receiver fast, giving up vertical space behind him. Mathieu understands that Bridgewater won’t have time to throw it deep — so if he’s throwing to that player, he’ll be throwing it right away.

Even when the aggression shows its vulnerabilities, a hurried, panicked quarterback can miss them at times — and that’s the payoff for continuing to send additional rushers. That’s what happens on this third-and-7.

The blitz from the left edge of the offense is counter by Bridgewater with a spin-out where he should have room to run or have time to pass. However, the defensive play called for defensive end Frank Clark to sink into a short zone. He immediately collapses and forces a throwaway.

Even if Clark had been rushing, all of the routes were running the opposite direction of where Bridgewater escaped — and two of them looked to be coming open. There would have been an available throw if Bridgewater had fled away from the pressure as he should have.

Pass-rush impact without sacks

The Chiefs forced two consecutive three-and-outs to start the game; the second third-down attempt was denied by the individual talent of multiple defensive linemen.

The Chiefs once again play man coverage on third down, using Mathieu in a robber-coverage role and Thornhill as the only deep safety. They trust their four-man rush to get it done with stunts; they can’t get the sack, but they make just as much of an impact.

First of all, both end-tackle pairings run stunts where the interior player penetrates the B-gap to give the edge player a lane to loop behind and come through the A-gap. This is a double whammy for defensive tackle Chris Jones; he can clear that lane while also still collapsing the pocket — and that’s exactly what he does here.

Bridgewater initially looks left, but Jones’ overwhelming size and initial penetration from that direction force the quarterback to come off of that first read and make something happen. As that begins, defensive tackle Jarran Reed — keeping his eyes up after pushing the B-gap on his side — quickly spins off and cuts Bridgewater’s path to escape the pocket off. The forced incompletion got them off the field.

Short-yard run defense

There were rough stretches for the Chiefs’ run defense in that game, but they came up big in multiple short-yard conversion scenarios.

Primarily, the unit stuffs this off-tackle run because of Mathieu’s presence. First of all, his pre-snap recognition allows him to be in a great position to impact the play. He flies to the path of the running back and disrupts the play’s most important block at the point of attack. His presence attracts the left tackle, who leaves defensive end Mike Danna in a position to make the tackle with strong help from cornerback Deandre Baker.

On the ridiculous, 20-play drive, the run defense stepped up to make the fourth-down stop after being gashed up and down the field.

Defensive tackle Jarran Reed wins with quick penetration and a swim move to move the running back off of his path, bumping him into Gay’s lap — who was so fast on the run blitz that the right guard didn’t get a hand on him. To finish the play, Ingram tosses the left guard aside right before making the final hit to confirm the fourth-down stop.

The bottom line

The Chiefs’ third-down defense has been incredibly effective because of aggressive, creative play calling by Spags, consistently impactful pass rush, and a stout run defense when they need it. The coverage has also been a huge part of this stretch — but the front seven was making most plays on third down against Denver.

Each level of the defense is seeing improvement from significant players; Jarran Reed, Willie Gay Jr., and Juan Thornhill all made huge impacts in this game.

It’s hard to find someone not playing well right now, and that’s precisely why the unit is now one of the league’s best defenses on third down,