luckadjusted
NFL Week 9 · 2026

Week 1 2026 · September 14, 2026

Broncos at Chiefs, Week 1 2026: who deserved to win?

The Chiefs beat the Broncos 31–10, and the replays back it up: with the way both teams actually played, the Chiefs win 9 of 10.

Before kickoff the Chiefs were 57% favorites. The biggest swing (Q2, 4:33 left): the Chiefs fumbled and recovered it themselves, worth 11 points of win probability to the Chiefs.

Final

Denver Broncos 10
Kansas City Chiefs 31

September 14, 2026 · GEHA Field at Arrowhead Stadium · Closing line: Chiefs −2.5

Our prediction before kickoff: Broncos by 0.7

Luck index +14 Chiefs about even · −14 Broncos

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. Broncos win 1, Chiefs win 9.

  1. 1 DEN 27 KC 20
  2. 2 DEN 20 KC 22
  3. 3 DEN 26 KC 31
  4. 4 DEN 14 KC 22
  5. 5 DEN 16 KC 28
  6. 6 DEN 19 KC 34
  7. 7 DEN 3 KC 20
  8. 8 DEN 20 KC 41
  9. 9 DEN 6 KC 31
  10. 10 DEN 3 KC 34

Our prediction before kickoff

We had the Broncos by 0.7, 52% to win. The Chiefs won by 21, a result we gave 48%. The final margin was 21.7 points from ours; 9% of games like this end further from the forecast than that.

Show as a table
OutcomeChance
Broncos win52.2%
Chiefs win47.8%
Middle 50%: Broncos by 10 to Chiefs by 750%
Middle 90%: Broncos by 22 to Chiefs by 2190%
Middle 95%: Broncos by 26 to Chiefs by 2495%
Exactly Broncos by 38.5%
Exactly Chiefs by 38.3%
Exactly Broncos by 75.1%
Exactly Chiefs by 74.8%
Exactly Broncos by 103.6%

Most of the distance between a forecast and a final score is luck: even with both teams’ strength known exactly, one game’s bounces, kicks and calls move the final margin by about ±12 points. This game was played before our forecasts went live, so this one was made afterwards, the same way, from only what was known before kickoff. How our predictions have done

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.

How 4,000 replays ended

Broncos win 14% of them, Chiefs 86%, counting the 2% still level after regulation as half each. The line is what actually happened: Chiefs by 21.

Show as a table
Final margin in the replaysShare of replays
Broncos by 17+1.1%
Broncos by 9–163.0%
Broncos by 1–89.4%
Level after regulation1.6%
Chiefs by 1–819.8%
Chiefs by 9–1624.0%
Chiefs by 17+41.0%

Where the luck was

What the luck was worth

Every lucky and unlucky play, weighted by the moment it happened: its swing in win probability, added up by kind. A missed kick in a decided game counts for nothing; the same kick at the end of a tie game can be most of a win.

Swings add up across a game, so in one that went back and forth they can pass 100%. On the scoreboard the same luck was worth +7.4 points to the Chiefs: the final margin was Chiefs by 21, without the luck Chiefs by 13.6. Luck shares are the fitted ones (how much of each kind is luck).

The kicks

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

  • W. Lutz, 31 yds made · 94% expected
  • H. Butker, 28 yds made · 98% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Broncos 7 for 52 yards, Chiefs 7 for 60 yards

Every accepted flag, in order, and what it did to the helped team’s chance of winning at that moment, including any play it wiped out (points on the scoreboard in grey). A flag in a decided game is worth nothing; one at the turn of a close game can be worth most of a win. Judgment calls count half toward luck; pre-snap fouls, which repeat, don’t count. How calls are valued

WhenFlagWin probability for
Q1 8:27 Offensive Holding on the Chiefs, 10 yards, wiping out the play +5% DEN +2.8 pts
Q1 7:30 Defensive Offside on the Chiefs (L'Jarius Sneed), 5 yards · pre-snap +3% DEN +0.6 pts
Q1 1:14 Offensive Holding on the Broncos (Pat Bryant), 10 yards +4% KC +0.9 pts
Q2 6:42 Offensive Holding on the Chiefs (Jack Cochrane), 10 yards +1% DEN +0.7 pts
Q2 0:58 Offensive Holding on the Chiefs (Jadon Canady), 9 yards +2% DEN +0.8 pts
Q3 10:28 Delay of Game on the Broncos, 5 yards · pre-snap +2% KC +0.9 pts
Q3 10:03 Delay of Game on the Broncos, 5 yards · pre-snap 0% KC +0.4 pts
Q3 10:03 Illegal Formation on the Chiefs (Jalen Royals), 5 yards · pre-snap 0% DEN +0.3 pts
Q3 9:34 Offensive Holding on the Broncos (Pat Bryant), 10 yards +2% KC +1.0 pts
Q3 1:09 Offensive Pass Interference on the Broncos (Troy Franklin), 10 yards, wiping out the play +4% KC +2.0 pts
Q4 15:00 Unnecessary Roughness on the Broncos (Alex Singleton), 2 yards 0% KC +0.6 pts
Q4 13:38 Unnecessary Roughness on the Chiefs (Cyrus Allen), 6 yards 0% DEN +0.5 pts
Q4 9:50 Chop Block on the Chiefs, 15 yards 0% DEN +1.4 pts
Q4 7:08 Offensive Holding on the Broncos (Tycen Anderson), 10 yards 0% KC +0.7 pts

Broncos penalties, every game · Chiefs penalties, every game · All teams, 2026

When it happened

Chiefs’ 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 Chiefs were ahead in it, below while the Broncos were.
#WhenWhat happenedWin probability forNext drive
1 Q1 11:35 The Chiefs converted 4th & 23rd & 4th downs · 61% expected +5% KC KC: Touchdown
2 Q1 8:27 Offensive Holding on the Chiefs, 10 yards, wiping out the playJudgment calls +5% DEN DEN: Touchdown
3 Q1 1:14 Offensive Holding on the Broncos (Pat Bryant), 10 yardsJudgment calls · 5 flags in 522 snaps before, position avg 1 per 399 +4% KC KC: Punt
4 Q2 11:21 The Chiefs fumbled and recovered it themselvesFumble bounces · loose balls are close to 50/50 +6% KC KC: Punt
5 Q2 8:41 The Chiefs converted 3rd & 83rd & 4th downs · 31% expected +6% KC KC: Punt
6 Q2 6:46 The Chiefs were stopped on 3rd & 23rd & 4th downs · 61% expected +4% DEN KC: Punt
7 Q2 4:37 K. Walker dropped a catchable passDrops · 10 drops on 155 catchable balls before this +5% DEN KC: Touchdown
8 Q2 4:33 The Chiefs converted 3rd & 103rd & 4th downs · 27% expectedThe Chiefs fumbled and recovered it themselvesFumble bounces · loose balls are close to 50/50 +11% KC KC: Touchdown

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.

  • Josh Simmons (KC T), out · 0.7 pts
  • Chamarri Conner (KC DB), out · 0.6 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

Broncos 2% · Chiefs 98%

Final margin
Chiefs by 21
Luck in points
7.4 for the Chiefs
Luck-adjusted margin
Chiefs by 13.6
Replay with same day's form
Broncos 14% · Chiefs 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

None by default: our tests measured no carryover after a lucky break. Slide it up to count a break for more than its own swing. 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 2026 games · Broncos · Chiefs

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