The Chiefs’ pass defense exposed holes that needed to be patched against the Broncos

To set up a potential game-winning field goal against the Kansas City Chiefs in Week 10, the Denver Broncos needed six yards to run down third down. Rookie quarterback Bo Nix dropped back, stepped up from the edge pressure and found wide receiver Courtland Sutton open beyond the sticks.

It was the sixth catch of the day for the number one receiver, including a 32-yard touchdown that pushed Denver’s lead to 14-3 in the first half. Cornerback Trent McDuffie had man-to-man coverage of Sutton at both crucial moments. The Chiefs’ top coverage player was responsible for 67 yards, the highest mark of any game this season PFF.

It was a challenging match for McDuffie, defending Sutton’s 6-foot-1, 216-pound frame. The 29-year-old receiver has endured quarterback challenges in Denver, but he showed why he is one of the most underrated receivers in the league in this area. He ran sharp routes and used his strength to subtly achieve separation.

It was a one-on-one battle that McDuffie can hang his hat on and still feel good about limiting himself to three impactful completions. Overall, the Chiefs defense held the Broncos to a manageable point total, but several key completions breathed new life into the upset bid.

The cover fails

On Denver’s first touchdown drive, a fumbled snap and penalty put the offense back on second and long. To defend the pass, the Chiefs come out in split-field coverage, asking defenders on the left side of the offense to play man coverage, and defenders on the right side to run zone coverage.

Cornerback Nazeeh Johnson starts in man coverage, but his receiver runs across the field into the zone side. He should let him go and find a receiver from the other direction to pick up, like the tight end that gets free in a shallow crossing route. Instead, Johnson continues to track the receiver and runs into linebacker Drue Tranquil, trying to pick up a deeper crossing pattern.

It leads to a gain of 34 yards, a pass that could have gone to either of the two receivers who broke open due to the coverage breakdown.

Schedule

The Broncos converted third-and-5 from the 6-yard line to punctuate the touchdown drive. The Chiefs got into zone coverage, but Denver had the perfect call to beat it.

Knowing Sutton is a strong threat in the red zone, the Chiefs targeted two players on him: cornerback Trent McDuffie and safety Justin Reid bracketed him from both ends. McDuffie’s responsibility makes the left flat vulnerable, so linebacker Drue Tranquill must cover the running back as he points outside.

Denver’s formation is strong to the right, drawing the rest of the Chiefs’ zone defenders to that side of the ball. There is no one left to cover the receiver working from right to left, leaving an open window to throw the touchdown.

Sutton’s severity forced the Chiefs’ hand; it was the second week in a row that defensive coordinator Steve Spagnuolo appeared to be outmatched on the red zone pass.

After allowing two passing touchdowns in the first half, Spags had to find ways to improve pass down coverage over the final two quarters.

To force punts on the two drives before the final possession, the Chiefs blitzed — and blitzed difficult. Each of these third downs had no chance of conversion as the rush outpaced the Broncos’ pass protection.

• While the Broncos’ three offensive linemen are occupied by defenders, linebacker Nick Bolton and safety Justin Reid both rush A holes, knowing the running back can only fill one. Nix has nowhere to escape Bolton.
• The Chiefs overwhelm the left side of the Broncos’ pass protection by sending two blitzers on top of the two traditional rushers. Denver’s left guard fails to pick off Reid, but even when he did, Nazeeh Johnson got free to force the same rushed throw.

The bottom line

The Chiefs defense has performed stronger this year, but the unit still made enough stops to expect to win. The Chiefs offense and quarterback Patrick Mahomes missed opportunities to score and turned it into a more comfortable victory.

That said, the Broncos used the final 5:57 of the game to nearly win in Kansas City. The 13-play drive moved the chains three times and Nix completed all five of his passes on possession. The final third down was converted with a downfield completion.

The Chiefs are feeling the absence of cornerback Jaylen Watson. The four-man pass rush will have to be more consistent than it was against Nix, and Johnson will have to settle into the second corner position and prove the coaching staff’s belief in him is correct. Third-string cornerback Joshua Williams played just six snaps against Denver.