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How the Chiefs offense beats the 49ers defense (part 1)

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The 49ers defense is tough, but other teams have found ways to succeed against their preferred Match 3 coverage.

Divisional Round - Minnesota Vikings v San Francisco 49ers Photo by Michael Zagaris/San Francisco 49ers/Getty Images

Super Bowl week is finally here! The Kansas City Chiefs and San Francisco 49ers are gearing for Sunday’s league championship.

Since it’s the season’s biggest game, we’re breaking our usual offense versus defense breakdown into two parts — this one focused solely on the 49ers defense and how other teams have attacked it. Later, the second part will examine how the Chiefs have dealt with similar defenses.

Let’s get to it!

NFC Championship - Green Bay Packers v San Francisco 49ers Photo by Michael Zagaris/San Francisco 49ers/Getty Images

Personnel

The 49ers defensive line is the strength the team — and it’s arguably the top unit in the NFL. Defensive end Nick Bosa — the NFL’s defensive rookie of the year — anchors one end. Across from Bosa on passing downs is former Kansas City Chiefs linebacker Dee Ford, who gets from a third to a half of the defensive snaps. Ford is almost exclusively a pass-rushing specialist and has been working through a hamstring injury for most of the year.

As dangerous as the 49ers’ edge rushers are, the Chiefs are pretty well-equipped to handle them; Eric Fisher and Mitchell Schwartz are one of the league’s better offensive tackle combinations.

Of greater concern to the Chiefs is the interior of the line. Arik Armstead plays outside — kicking inside for passing downs — while DeForest Buckner is one of the more underrated defensive tackles in the NFL. The length and athleticism of these two players create problems for most teams — but could create bigger ones for the Chiefs, as that is where their offensive line is weakest. Solomon Thomas and Sheldon Day — who provide the ability to penetrate quickly — round out the rotation.

Inside linebacker Fred Warner leads the 49ers’ second level. He has quickly risen to be one of the NFL’s best — and most complete — players at his position. His athleticism — along with ability in coverage and as a blitzer — allow him to make plays all over the field. Kwon Alexander is a high-priced, highly-talented linebacker who provides top-notch athleticism. Rookie linebacker Dre Greenlaw has been a huge surprise for the 49ers; he filled in very well when Alexander missed time.

While this group of linebackers is very talented and quite athletic, they are all prone to being over-aggressive; they can be manipulated out of their spots. If Greenlaw or Alexander are regularly used in coverage, it could be an area on which the Chiefs could focus; Greenlaw’s athleticism can be challenged and Alexander is still working back from injury.

Cornerback Richard Sherman leads the 49ers’ secondary. He is back to his elite form following an Achilles injury a couple of years ago. While Sherman does get some protection from the 49ers’ scheme, they have sometimes let him travel — and he’s been phenomenal this season. Across from him, Emmanuel Moseley has taken the starting job from Ahkello Witherspoon. While he’s been playing well — and will make flash plays — he can be vulnerable.

The nickel cornerback is K’Waun Williams — a steady player in the slot. Jimmie Ward and Jaquiski Tartt are the safeties. Both add stability and leadership to the secondary — but in the playoffs, the Chiefs have already been able to take advantage of some good safeties. The biggest challenge for the 49ers secondary will be the Chiefs’ speed; the mid-4.4 speed of their secondary won’t match well against the 4.3-flat speed that Chiefs receivers possess.

Match 3 coverage

The 49ers don’t run the same coverage on every snap, but they do rely on their Seahawks-style Cover 3.

While it might have been just to put it on film, there was a stretch late in the season in which the 49ers ran lots of man coverage. But the second-most common shell they use is Quarters. There is more to the 49ers coverage than there was to the classic Seahawks defense, but they still lean heavily on that Cover 3 scheme — which is really Match 3.

Here it is: three deep defenders and four underneath. There are no players dedicated to the flat (or up the seams) — but with match principles, the Apex (slot) defender should be working into those areas.

As long as the outside cornerbacks can be threatened by an outside wide receiver, one of the biggest weaknesses of any Cover 3 variant is the seams.

In this play, the wide outside release from the secondary receivers force the Apex defender to widen his drop before the receivers cut upfield and run to open space.

The game plan the Los Angeles Chargers used against the Chiefs is getting a lot of attention this week. While it looked solid on paper — we’ll get more into that in part two — the simple way to attack a team that is terrified to get beaten deep is with short, simple timing routes.

Whenever the underneath defenders are focused on getting depth in their drop, these Hitch-Flat or Slant-Flat combos will be open. The idea here is to sustain drives by challenging the defense to make stops in the open field against talented skill players. It’s similar to how a defense can challenge an offense to dink and dunk down the field; an offense can challenge the defense to stay passive on the back end while giving up long drives.

Simple execution in some one-on-one situations can pressure the 49ers defense.

Here, the post route on the backside is open for a second — that is, if you want to challenge that window — but on the strong side, there’s a wide receiver against a cornerback who is being forced to protect vertically while in one-on-one. If the wide receiver is pressuring vertically, deep out-breaking or back-breaking routes can be open all day.

This is a little preview of something the 49ers will do against deep cross-field routes — but we’re simply focusing on the levels concept.

Whether you want to run a dagger concept with a slot receiver running a nine route and the wideout running a dig route — or a follow/levels concept like this — a deep dig route is often open against Cover 3. You just clear out the underneath coverage to hit the deep dig behind it.

3x1 adjustment

Here’s a common adjustment for the 49ers — or for any team playing the Chiefs: this weak side buzz.

The hook defender on the weak side — opposite of the three-wide receiver set — doesn’t play in the hook, but instead goes deep into the high hole so he can carry a vertical route across the field. This is designed to take away the four verticals concept — which often has a deep over route from the number three-wide receiver — that the Chiefs love to run.

To take advantage of it, the Los Angeles Rams run this Over-Stop route. The weak side hook defender climbs to depth while the strong hook defender has to widen with the threat of a third wideout to his side. This opens up the middle of the field — against a defense that is designed to take it away.

Another relatively easy way to attack the 3x1 buzz adjustment is to align the running back to the side of the three receivers; this forces the underneath coverage to make a push call and widen their zones.

On this play, the Green Bay Packers don’t take advantage — but what happens is that the Apex defender either has to widen and eye the flat, or the linebacker has to work over to the flat. Either way, there is going to be a gap in the zone as the defense tries to cover the space.

Rather than using the late-running release and the Nine-Hitch combination on the outside, like the Packers did, a team could stress the outside cornerback and deep safety by simply running verticals from this 4x1 look. Since the altered angle on the deep over is more vertical, this also gives leverage; the deep safety has to honor the strong side vertical.

While attacking the buzz adjustment with these verticals, trusting receivers’ speed could be a big-play factory.

It’s not just a vertical attack that can succeed against a Cover 3 weak side buzz defense. This screen by the Rams uses its rules against it.

The motion into the 3x1 set gives the 49ers defense the same buzz alert; the deep over is still a threat. But the weak cornerback, weak Apex, deep safety and weak side buzz defender are all completely out of this screen play; they have to hold their assignments. For the offense, the numbers on the screen are overwhelming.


Later this week, we’ll dive into how the Chiefs have found success using similar concepts against similar coverage. You can also check out two Twitter threads — this one and this one — with more examples showing the 49ers defense and some of their adjustments.