In hindsight, it is not so hard to understand how the Kansas City Chiefs offense collapsed the way it did. The offensive line was decimated, both due to injuries from earlier in the season as well as injuries to left tackle Eric Fisher in the playoffs. Star quarterback Patrick Mahomes also had turf toe, which only served to exacerbate any issues with the offensive line. The Chiefs offense was not operating at full capacity.
Now, that is not an excuse, nor is it a means to downplay what the Bucs defense did on Sunday. Holding Mahomes to zero touchdowns is a feat, regardless of circumstance. Tampa Bay still had to craft a sharp game plan to take advantage of Kansas City's offense being hobbled.
We can suggest a number of factors, both in terms of scheme and execution, as the reason the Bucs came out on top. The pass rush was dominant all game long and with very few added blitzers, which is uncharacteristic of a Todd Bowles-led defense. Tampa Bay's cornerbacks played tough, effective press coverage all game. Bowles, in contrast to his typical approach, turned to a ton of two-deep coverages to put a hard cap on Kansas City's vertical game. It was a master class from both the coaches and players.
The culmination of all those factors working together was how well the Bucs defense took away the intermediate-to-deep middle area from Mahomes. Whether it was good zone spacing, posting the No. 3 (innermost receiver) against trips, or poaching over routes with the back-side safety, the Bucs defense almost always had an answer for the posts, seams, and overs that the Chiefs live off of. Mahomes was regularly forced to move onto his next read, which often led to him bailing out of the pocket considering how the Bucs' front was performing.
Below is one of the few instances in which the Bucs brought pressure on Sunday. The Bucs show five on the line of scrimmage from this 3-2-6 dime personnel, putting both linebackers over a guard. The linebackers pop off the line of scrimmage, while blitzing safeties replace them on either side to create a three-deep, three-under pressure. Doing so puts a lot of pressure on the linebackers to bail, locate the biggest threat to their zone, leverage it, and get eyes back to the quarterback.
Devin White (45) does a great job popping off the line of scrimmage over the right guard to do just that. White gets his depth in a hurry, then flips his hips back open and slides back to the middle of the field (right across the Super Bowl LV logo) with eyes on the quarterback, squeezing the window on the middle curl so that it's never open between White and Lavonte David's zone on the opposite side of the field. Wide receiver Tyreek Hill does well to recognize the broken play and get vertical, and it almost works out for the Chiefs, but White did well to shut down this play the way it's drawn on the whiteboard. Though not the sexiest play, it's good, sound defensive football.
This time, White (right hash) is the "poster" in a match-quarters coverage. White is responsible for walling off the No. 3 receiver from cutting inside and re-routing him vertically. With speed (i.e., a wide receiver) at the No. 3 spot, it's common for defenses to check to a call that will not ask the linebacker to carry the No. 3 and instead post it off for a poaching safety, which is what happens here. Even as fast as Hill (the No. 3 here) is off the line of scrimmage, White still manages to expand and contact him just enough to force him to widen a bit before he runs the deep over route. Mahomes opens to the weak side and is forced to bail out of the pocket before getting his eyes over to the strong side anyway, but it's still good process from White to post this well enough to pass it off to the poaching safety on the back side.
Here is another example of the strong-side linebacker playing with good spacing to pass off a route to a poaching safety. In this case, the strong-side linebacker is David (54, to the offense's right), who quite often followed Travis Kelce across the field. Even in the previous clip, David was playing weak because Kelce was to that side, yet he's playing strong here because Kelce is to that side. Anyway, David does well to expand into Kelce while gaining depth to the sticks, then flip his hips and eyes inside once Kelce gets past him. David's excellent spacing and eyes on the quarterback squeeze the window on this route right into the poaching safety, whose job is to handle the No. 3 vertical and/or across the field at this depth. Mahomes tries to hold out for his tight end to get open, but Kelce never does, resulting in a huge first-down sack for the Bucs.
The Bucs are poaching with the back-side safety again here. Antoine Winfield Jr. (31) is the poach player outside the right hash. As soon as Winfield sees the iso wide receiver do anything other than immediately burst off the line of scrimmage (i.e., to threaten a dig, post, etc.), it's his job to get his eyes back to the field and poach any crossers/overs coming back to him. With some help from nickel Sean Murphy-Bunting squeezing the No. 2 across the field, the middle of the field once again gets closed on Mahomes, forcing another sack.
Some of the Bucs' match coverages instead had the strong safety picking up the No. 3 vertical and/or across the field. Which style of match coverage the Bucs (or any defense) wants to play just depends on what or who exactly the defense wants to take away. If an offense's key threats (or "speed") are to the trips side, maybe keeping the strong safety over top and having the safety poach (and leaving the iso receiver with less guaranteed coverage) is the move. On the flip side, if the offense has their best guy all alone opposite the trips side, maybe locking the weak safety into a deep-half to ensure extra help over the top there is better.
Here is a good clip of the latter. To the bottom of the screen, cornerback Carlton Davis is in press coverage with a safety bailing deep and wide to play a deep half. The Bucs are not letting Hill, the iso receiver, win over the top. To the strong side, the safety is reading the stems of the No. 2 and No. 3 to match them vertically. The No. 2 goes under early and the No. 3 gets vertical beyond 5 yards, prompting the safety to match the deepest of the two threats, the No. 3. Mahomes tries to work back to the No. 3 cutting inside, but the safety drives on the inside shoulder in a hurry and takes the No. 3 away, again forcing Mahomes to scramble around.
Everything the Bucs defense did felt one step ahead of the Chiefs offense. The game plan was excellent and all 11 players did their jobs. Mahomes still had his usual handful of hero plays, but the Chiefs' down-to-down consistency just was not there because of how well the Bucs defense executed their plan.
It was a perfect confluence of factors for the Bucs. A slightly-hobbled Mahomes behind an all-time horrific offensive line is a good place to start for any defense. Still, it was a historic performance against an otherwise unstoppable Chiefs offense, and the Bucs defense deserves all the praise in the world for pulling it off on the biggest stage.