luckadjusted

Week 1 2025 · September 5, 2025

Chiefs vs Chargers, Week 1 2025: who deserved to win?

The Chargers beat the Chiefs 27–21, and it was no fluke: replayed with the way both teams actually played, the Chargers win 9 of 10. The Chiefs had the bounces: fumble bounces alone were worth 1.6 points to the Chiefs.

An off day for the Chiefs: their defense played far below its usual level. In a fresh game against the Chargers they would win 53% of the time; with this day’s form, 14%. The numbers

Before kickoff the Chiefs were 59% favorites. The biggest swing (Q4, 3:24 left): the Chiefs converted 4th & 7, worth 11 points of win probability to the Chiefs.

Final

Kansas City Chiefs 21
Los Angeles Chargers 27

September 5, 2025 · SoFi Stadium · Closing line: Chiefs −3

Luck index +14 Chargers about even · −14 Chiefs

Each team’s own plays from this game, resampled into new drives 4,000 times: with the way both teams actually played, how often does this performance win? How the replay works

Ten replays. Chiefs win 1, Chargers win 9.

  1. 1 KC 27 LAC 21
  2. 2 KC 26 LAC 28
  3. 3 KC 3 LAC 7
  4. 4 KC 10 LAC 17
  5. 5 KC 17 LAC 26
  6. 6 KC 17 LAC 28
  7. 7 KC 14 LAC 27
  8. 8 KC 3 LAC 20
  9. 9 KC 3 LAC 24
  10. 10 KC 13 LAC 41

Three other ways to ask

Each answers a different question, so none of them replaces the replay above.

The closing betting line, turned into a probability. What everyone knew before the game.

The line plus what this game showed, weighted by how much one game can tell. It stays close to the line because one game says little.

Every kick, fumble bounce, drop, conversion and judgment call redrawn; everything else fixed. The narrowest view of luck.

An off day for the Chiefs

Their defense played far below its usual level. In a fresh game against the Chargers they would win 53% of the time; with this day’s form, 14%.

39 points apart for the Chiefs: the gap is how differently this game went from what the two teams usually are.

UnitThis gameUsual levelBetter or worse than usual
Chiefs offenseEPA per play gained +0.12 +0.14 worse by 0.01
Chiefs defenseEPA per play allowed +0.32 +0.09 worse by 0.23
Chargers offenseEPA per play gained +0.32 +0.09 better by 0.23
Chargers defenseEPA per play allowed +0.12 +0.07 worse by 0.05

EPA (expected points added) per play on competitive snaps, turnovers left out because they are valued as luck. Usual level: the team’s earlier games this season plus half of last season, pulled toward the league average. One team’s defense and the other team’s offense are the same snaps, so one game can’t fully say whose day it was; it shows how far this one was from both teams’ norms.

How 4,000 replays ended

Chiefs win 14% of them, Chargers 86%, counting the 1% still level after regulation as half each. The line is what actually happened: Chargers by 6.

Show as a table
Final margin in the replaysShare of replays
Chiefs by 17+0.5%
Chiefs by 9–163.4%
Chiefs by 1–89.6%
Level after regulation0.9%
Chargers by 1–828.1%
Chargers by 9–1624.4%
Chargers by 17+33.1%

Where the luck was

Take the luck out

The final margin was Chargers by 6. Remove the luck, one kind at a time, and it becomes Chargers by 6.8.

Each row takes one kind of luck out of the margin. Color shows which team it helped. Luck shares are the fitted ones (how much of each component is luck).

The kicks

How likely each kicker was to make that kick (his own record, the distance and the weather), and what happened.

  • C. Dicker, 39 yds made · 92% expected
  • H. Butker, 35 yds made · 95% expected
  • C. Dicker, 36 yds made · 95% expected
  • H. Butker, 59 yds made · 65% expected
  • H. Butker, 27 yds made · 99% expected
  • Extra point missed · 95% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

When it happened

Chargers’ chance of winning

Numbers mark the biggest luck moments, listed below.

nflfastR’s in-game win probability. It ignores the betting line, so it starts near even. Shaded above the middle while the Chargers were ahead in it, below while the Chiefs were.
#WhenWhat happenedWin probability forNext drive
1 Q2 8:45 The Chiefs converted 4th & 13rd & 4th downs · 75% expected +6% KC KC: Field goal
2 Q2 0:03 H. Butker made 59-yard field goalKicks · 65% expected for him, 45 of 61 from 45+ before +7% KC KC: Touchdown
3 Q3 10:10 The Chiefs converted 3rd & 83rd & 4th downs · 33% expected +7% KC KC: Touchdown
4 Q3 8:05 The Chiefs missed an extra pointKicks · extra points are made about 94% of the time +7% LAC KC: Touchdown
5 Q3 5:46 The Chargers converted 4th & 13rd & 4th downs · 74% expected +6% LAC LAC: Touchdown
6 Q3 0:36 The Chargers converted 3rd & 33rd & 4th downs · 53% expected +8% LAC LAC: Touchdown
7 Q4 12:04 The Chiefs’ two-point try failed3rd & 4th downs · 47% expected +7% LAC KC: Field goal
8 Q4 3:24 The Chiefs converted 4th & 73rd & 4th downs · 36% expected +11% KC KC: Field goal

Missing players

Key players (usually on the field for half the snaps or more) who missed this game or part of it, valued by position and quality. The same players are missing in every replay, so this counts as luck in points only.

  • Rashawn Slater (LAC T), out (IR) · 1.0 pts
  • Josh Harris (LAC LS), out (IR) · 0.1 pts

Adjust the assumptions

Disagree with how much of a fumble bounce or a pass interference call is luck? Change it and the coin-flip replay reruns in your browser.

Only coin-flips re-rolled

Chiefs 19% · Chargers 81%

Final margin
Chargers by 6
Luck in points
0.8 for the Chiefs
Luck-adjusted margin
Chargers by 6.8
Replay with same day's form
Chiefs 14% · Chargers 86% unchanged: why
How much of each is luck?

0% treats it as skill, 100% as pure luck. The tick is our fit.

What counts

We tested momentum on 19,000 lucky breaks and found none, so it's off by default. Why

Flip a play

Force the other outcome, in this game and in every replay: a made kick becomes a miss, a stop becomes a conversion, a flag goes the other way.

About these numbers

Play-by-play and win probability from nflfastR via nflverse; kicks valued against each kicker’s own record; drops and interception-worthy throws from FTN charting; injuries from snap counts and injury reports.

Methodology and validation · All Week 1 2025 games · Chiefs · Chargers

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