In a Season of Attrition, the Chiefs' Defense Deserves Credit for KC's Undefeated Start

On an offense-dominated team in an offense-first league, the Kansas City Chiefs' defense deserves more than its fair share of credit for KC's 6-0 start.

Oct 20, 2024; Santa Clara, California, USA; San Francisco 49ers wide receiver Brandon Aiyuk (11) lays on the ground after suffering an injury against the Kansas City Chiefs in the second quarter at Levi's Stadium. Mandatory Credit: Cary Edmondson-Imagn Images / Cary Edmondson-Imagn Images

The Kansas City Chiefs are the NFL's lone undefeated squad, now boasting a 6-0 record after a 28-18 win over the San Francisco 49ers on Sunday. Even more importantly, no other AFC team has fewer than two losses, giving KC a remarkable early lead for the No. 1 seed in the conference.

Most of the conversations regarding the reigning back-to-back champions has, understandably, been about the Chiefs' offense. The team has its No. 1 and No. 2 wide receivers on injured reserve along with their starting running back, and quarterback Patrick Mahomes has been fine by his standards, but certainly not his absolute best. And yet, here they are, alone atop the NFL. It seems like a bit of a magic trick at first glance. Kansas City, nearly weaponless with an imperfect two-time MVP at quarterback, undefeated?

I'm not sure if I completely buy the old saying that "defense wins championships," but it has certainly won more than its fair share of the Chiefs' first six games.

On Sunday, the 49ers scored 18 points. Those 18 points arrived by way of one short field goal drive, one long end-of-half field goal drive, one 23-yard touchdown drive following an interception deep in Chiefs territory, and one touchdown drive in the 49ers' last-gasp effort before KC iced the game. That's not a completely immaculate effort, but it's pretty darn close. Incredibly, it's also not unfamiliar.

As Tom Brady frequently noted on the broadcast, 49ers quarterback Brock Purdy seemed unsettled throughout much of the game, likely due in large part to the advantage Chiefs defensive coordinator Steve Spagnuolo seems to consistently produce over 49ers head coach Kyle Shanahan's offense. Even without starting defensive end Mike Danna, the Chiefs' pass-rush (led by Chris Jones) impacted Purdy while the secondary combined for three interceptions, capitalizing on San Francisco's offensive miscues. According to Next Gen Stats, all three picks came with the Chiefs' secondary playing man coverage, while KC's outside corners played press coverage 59.8% of the time, a season-high mark.

In the running game, the Chiefs' defense dominated on the ground once again, holding starting running back Jordan Mason to 58 yards on 14 carries, making him the sixth-consecutive opposing starting running back to be held under 60 yards this season. (Derrick Henry: 46 rushing yards. Zack Moss: 34. Bijan Robinson: 31. J.K. Dobbins: 32. Alvin Kamara: 26.) Mason now has the most productive running back rushing performance against the Chiefs this season, and he didn't hit the 60-yard mark.

Much of the success of the Chiefs' defense has come from its remarkable continuity. Across the entire KC defense leading up to Sunday's game, the most-used newcomer in 2024 was rookie safety Jaden Hicks, who had played just 13 snaps through the first five games. Undrafted rookie Chris Rolland-Wallace was forced into action for the first major opportunity of his NFL career on Sunday, and despite joining a unit completely founded on players who have at least one season of experience in Spagnuolo's defense, Hicks and Rolland-Wallace each recorded one of Purdy's three interceptions, with veteran safety Justin Reid getting the third.

Now, that continuity will likely be tested with starting cornerback Jaylen Watson expected to miss time due to an ankle injury suffered on Sunday. After the game, head coach Andy Reid acknowledged that he feared Watson's injury would lead to a long-term absence.

"Yeah, I think Jaylen will be, yeah," Reid said. "I think. I mean, we'll see what the MRI says, but I don't think that's going to be great news."

Nate Taylor of The Athletic noted that he spotted Watson "on crutches with his left ankle [and] foot in a cast" after the game.

Losing Jaylen Watson would be a really, really big deal. This defense has thrived with continuity, and I'm not sure if the other guys can provide that level of stability and consistency. Hoping it's less than season-ending. https://t.co/jGlLysvBJl

— Joshua Brisco (@jbbrisco) October 21, 2024

Even with an apparent demotion for Joshua Williams and some difficult reps for Nazeeh Johnson, no coaching duo in the league has earned more trust in talent development than Spagnuolo and defensive backs coach Dave Merritt. With absurd consistency, Spagnuolo and Merritt have gotten the best out of their corners, with McDuffie (the No. 21 overall pick in the 2022 NFL Draft) and Watson (the No. 243 overall pick in 2022) as the two prime examples from opposite ends of the same draft class. An excellent college player (McDuffie) has evolved into a superstar, fourth-round pick L'Jarius Sneed blossomed into one of the league's best corners during his time in KC, and players like Watson, Johnson, Williams and safety/nickel back Chamarri Conner have already overachieved their draft slots. Now, even Rolland-Wallace could be on a familiar track.

The cornerback room had cause for concern in training camp, so a seamless "next man up" bet certainly isn't guaranteed, but whoever sees the largest increase in role will be joining a defensive backfield highlighted by the aforementioned corners as well as Reid and Bryan Cook at the safety position. With Spagnuolo and Merritt leading the way, it would be foolish to assume this will be the time the unit can't recalibrate to keep the defense thriving.

Read More: Four Takeaways from the Kansas City Chiefs' 28-18 Win Over the San Francisco 49ers