The rivalry used to be predictable. You knew how it went. The Chargers would play three quarters of brilliant, heart-stopping football, only for Patrick Mahomes to do something impossible in the final two minutes. It was a loop. A glitch in the matrix that Los Angeles fans lived through year after year.
But the 2025 season changed the math.
When Jim Harbaugh walked into the building, everyone expected "cloud of dust" football. They expected a boring, grind-it-out style designed to keep Mahomes off the field. Instead, what we got in the Los Angeles Chargers vs Kansas City matchups this past year was a tactical masterclass that caught the reigning champs leaning the wrong way.
The Brazil Breakthrough and the Harbaugh Effect
It started in Sao Paulo. Week 1. The NFL took this rivalry to Brazil, and most experts figured the Chiefs would treat it like a vacation. They hadn't lost an opener in years. But Justin Herbert showed up and played like a man possessed, throwing for 318 yards and three scores.
What was weird about that game? The Chargers didn't just run the ball.
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Harbaugh and Greg Roman—the guy famous for heavy run schemes—came out throwing on 7 of their first 8 plays. It was a total head-fake. Steve Spagnuolo, the Chiefs' defensive wizard, had his guys stacked in the box to stop the run, and Herbert just carved them up.
The most iconic moment wasn't a pass, though. It was Herbert's 19-yard scramble on 3rd-and-14 to ice the game. He slid, stared at the Chiefs' sideline, and basically signaled that the seven-game losing streak against Kansas City was dead. That 27-21 win wasn't a fluke; it was a blueprint.
Why the Chiefs Looked Human in 2025
Let's be honest, Kansas City had a weird year. By the time they met the Chargers again in December at Arrowhead, they were 6-7. Injuries were piling up like a multi-car pileup on the I-405.
- The O-Line Crisis: In that Week 15 game, the Chiefs were missing three starting offensive linemen. Jawaan Taylor and Trey Smith were out. Mahomes spent most of the afternoon running for his life from Khalil Mack and Tuli Tuipulotu.
- Missing Weapons: Hollywood Brown was inactive. Xavier Worthy had been banged up since the collision in the Brazil game.
- The Defensive Gap: Trent McDuffie being out in the second matchup left a hole in the secondary that even Spagnuolo couldn't scheme around.
The Chargers walked into Arrowhead and won 16-13. It wasn't pretty. It was a mud-fight. But it completed the season sweep—the first time the Chargers swept the Chiefs since 2013.
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Herbert vs. Mahomes: The Gap is Closing
For a long time, the "stat nerds" loved Herbert, but the "rings" crowd pointed at Mahomes. It's a fair argument. Mahomes has the hardware. But if you look at their head-to-head history, the games are almost always within one score.
Mahomes still leads the all-time head-to-head, but the 2025 season saw Herbert break Mahomes’ record for the fastest player to reach 1,700 completions. He also passed Peyton Manning for the most passing yards through the first six seasons of a career.
The difference now? The Chargers finally have a defense that doesn't melt down in the fourth quarter. In the past, Herbert would give the team a lead with 90 seconds left, and the defense would give up a 75-yard drive in 40 seconds. Under Harbaugh, that "Chargering" seems to have vanished.
Historical Context Most People Forget
This rivalry actually dates back to 1960. They were the Dallas Texans and the Los Angeles Chargers back then. The very first game between them was a 21-20 win for the Chargers.
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Since then, it's been a game of streaks.
- The Chiefs had a 9-game win streak from 2014 to 2018.
- The Chargers had a 6-game streak in the early 80s.
- Overall, Kansas City still leads the series 71-60-1.
But streaks are meant to be broken. The Chargers being one of the few teams with a losing record against every single division rival is a stat that Harbaugh clearly has pinned to the bulletin board. You can feel the culture shifting from "happy to be here" to "expecting to win."
What to Watch Moving Forward
The dynamic has shifted from Mahomes vs. Everyone to a genuine chess match between Harbaugh and Andy Reid. These are two Hall of Fame-caliber coaches who fundamentally disagree on how to win a football game. Reid wants to out-finesse you; Harbaugh wants to out-tough you.
Tactical Keys for Future Matchups:
- Pressure without Blitizng: The Chargers found success by letting their front four get to Mahomes. If you blitz him, he kills you. If you can drop seven into coverage and still make him uncomfortable, you win.
- The "Lambert-Smith" Factor: Keep an eye on the young receivers. KeAndre Lambert-Smith and Tre’ Harris stepped up big in 2025. The Chargers' ability to develop cheap, rookie talent at WR is what will allow them to keep paying Herbert his massive contract.
- Mahomes' Mobility: As Patrick gets older, he's actually running more. He had over 400 rushing yards in 2025. Accounting for his legs on 3rd-and-short is still the hardest job in the NFL.
If you're betting on these games or just watching as a fan, the "under" is becoming a more attractive play. These aren't the 42-41 shootouts of the mid-80s anymore. They are physical, defensive battles where the first team to 20 usually wins.
Actionable Insights for Fans:
- Track the Inactive List: This rivalry is currently being decided by the health of the offensive lines. If the Chiefs are missing two or more starters upfront, the Chargers’ pass rush becomes an automatic play.
- Watch the First 15 Plays: Harbaugh likes to "show" a look early to see how the defense reacts. If they come out in heavy personnel (3 tight ends) but throw the ball, it means they've spotted a mismatch in the secondary.
- Expect Close Finishes: Even in a "down" year for KC, they rarely lose by more than a touchdown. Since 2020, almost 80% of these games have been decided by 7 points or fewer.
The narrative that the Chargers can't beat the big bad wolf is gone. They've slayed the dragon. Now the question is whether they can sustain it or if Mahomes will remind everyone why he's the king of the AFC West in 2026.
Keep an eye on the 2026 draft. Both teams are desperate for interior defensive line depth. Whoever wins that battle in the trenches during the offseason will likely carry the momentum into their next meeting at SoFi Stadium.