luckadjusted
NFL Week 9 · 2026

Week 2 2021 · September 19, 2021

No FTN charting for this game (drops and interception-worthy throws are not modelled).

Cowboys at Chargers, Week 2 2021: who deserved to win?

The Cowboys beat the Chargers 20–17, and the replays lean their way: with the same day's form, they win 6 of 10.

Before kickoff the Chargers were 59% favorites. The biggest swing (Q4, 0:04 left): G. Zuerlein made a 56-yard field goal, worth 29 points of win probability to the Cowboys.

Final

Dallas Cowboys 20
Los Angeles Chargers 17

September 19, 2021 · SoFi Stadium · Closing line: Chargers −3

Luck index +38 Cowboys lucky · −38 Chargers

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. Cowboys win 6, Chargers win 4.

  1. 1 DAL 38 LAC 17
  2. 2 DAL 30 LAC 16
  3. 3 DAL 31 LAC 20
  4. 4 DAL 24 LAC 16
  5. 5 DAL 17 LAC 13
  6. 6 DAL 17 LAC 15
  7. 7 DAL 13 LAC 16
  8. 8 DAL 7 LAC 13
  9. 9 DAL 17 LAC 27
  10. 10 DAL 13 LAC 31

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

Cowboys win 62% of them, Chargers 38%, counting the 3% still level after regulation as half each. The line is what actually happened: Cowboys by 3.

Show as a table
Final margin in the replaysShare of replays
Cowboys by 17+11.8%
Cowboys by 9–1617.0%
Cowboys by 1–830.8%
Level after regulation2.6%
Chargers by 1–820.8%
Chargers by 9–1612.2%
Chargers by 17+4.9%

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 +8.3 points to the Cowboys: the final margin was Cowboys by 3, without the luck Chargers by 5.3. 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.

  • T. Vizcaino, 46 yds made · 81% expected
  • T. Vizcaino, 44 yds missed · 85% expected
  • T. Vizcaino, 32 yds made · 96% expected
  • G. Zuerlein, 34 yds made · 93% expected
  • T. Vizcaino, 29 yds made · 97% expected
  • G. Zuerlein, 56 yds made · 65% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Cowboys 8 for 76 yards, Chargers 12 for 99 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 12:03 Defensive Pass Interference on the Chargers (Kyzir White), 4 yards +7% DAL +2.6 pts
Q2 15:00 False Start on the Chargers (Josh Palmer), 5 yards · pre-snap +1% DAL +0.5 pts
Q2 14:23 Taunting on the Chargers (Keenan Allen), 15 yards +4% DAL +1.4 pts
Q2 13:56 Defensive Pass Interference on the Cowboys (Jayron Kearse), 13 yards, wiping out the play +11% LAC +3.6 pts
Q2 11:59 Offensive Holding on the Chargers, 10 yards, wiping out the play +3% DAL +1.6 pts
Q2 10:35 False Start on the Chargers, 5 yards · pre-snap +1% DAL +1.0 pts
Q2 6:44 Offensive Holding on the Cowboys, 10 yards +2% LAC +1.3 pts
Q2 5:57 Delay of Game on the Cowboys, 5 yards · pre-snap +2% LAC +0.8 pts
Q2 3:04 Offensive Holding on the Chargers, 10 yards +10% DAL +1.5 pts
Q2 2:00 Roughing the Kicker on the Cowboys, 15 yards +14% LAC +3.2 pts
Q2 1:53 Offensive Pass Interference on the Chargers (Jalen Guyton), 10 yards, wiping out the play +10% DAL +1.8 pts
Q2 0:17 False Start on the Chargers (Keenan Allen), 5 yards · pre-snap +3% DAL +0.3 pts
Q2 0:07 Face Mask on the Chargers, 15 yards +6% DAL +1.4 pts
Q3 13:09 Ineligible Downfield Pass on the Chargers, 5 yards, wiping out the play +15% DAL +3.0 pts
Q3 5:11 Delay of Game on the Cowboys, 5 yards · pre-snap 0% LAC +0.1 pts
Q3 3:10 Defensive Holding on the Cowboys (Trevon Diggs), 5 yards +1% LAC +0.3 pts
Q3 1:24 Offensive Holding on the Chargers (Jared Cook), 10 yards, wiping out the play +25% DAL +3.9 pts
Q3 1:15 Unnecessary Roughness on the Cowboys (Trevon Diggs), 13 yards +7% LAC +1.6 pts
Q4 5:42 Illegal Shift on the Chargers, 5 yards, wiping out the play · pre-snap +9% DAL +1.6 pts
Q4 3:54 Offensive Holding on the Cowboys (Jabril Cox), 10 yards +2% LAC +0.9 pts

Cowboys penalties, every game · Chargers penalties, every game · All teams, 2021

When it happened

Chargers’ chance of winning

As low as 0% and as high as 70%. 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 Cowboys were.
#WhenWhat happenedWin probability forNext drive
1 Q2 13:56 Defensive Pass Interference on the Cowboys (Jayron Kearse), 13 yards, wiping out the playJudgment calls · 4 flags in 1146 snaps before, position avg 1 per 530 +11% LAC LAC: Touchdown
2 Q2 2:00 Roughing the Kicker on the Cowboys, 15 yardsJudgment calls +14% LAC LAC: Missed field goal
3 Q2 1:53 Offensive Pass Interference on the Chargers (Jalen Guyton), 10 yards, wiping out the playJudgment calls · 4 flags in 1060 snaps before, position avg 1 per 399 +10% DAL DAL: End of half
4 Q2 0:07 T. Vizcaino missed a 44-yard field goalKicks · 85% expected for himFace Mask on the Chargers, 15 yardsJudgment calls +23% DAL LAC: Field goal
5 Q3 13:09 Ineligible Downfield Pass on the Chargers, 5 yards, wiping out the playJudgment calls +15% DAL DAL: Punt
6 Q3 12:32 The Chargers converted 3rd & 153rd & 4th downs · 24% expected +12% LAC LAC: Field goal
7 Q3 1:24 Offensive Holding on the Chargers (Jared Cook), 10 yards, wiping out the playJudgment calls · 6 flags in 1113 snaps before, position avg 1 per 269 +25% DAL DAL: Field goal
8 Q4 0:04 G. Zuerlein made a 56-yard field goalKicks · 65% expected for him, 21 of 32 from 45+ before +29% DAL –

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.

  • Bryan Bulaga (LAC T), out (IR) · 0.5 pts
  • Justin Jones (LAC DT), out · 0.3 pts
  • Michael Gallup (DAL WR), out (IR) · 0.9 pts
  • Donovan Wilson (DAL S), out · 0.4 pts
  • Hunter Niswander (DAL P), out (IR) · 0.2 pts
  • Neville Gallimore (DAL DT), 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

Cowboys 20% · Chargers 80%

Final margin
Cowboys by 3
Luck in points
8.3 for the Cowboys
Luck-adjusted margin
Chargers by 5.3
Replay with same day's form
Cowboys 62% · Chargers 38% 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 (not available for this game); injuries from snap counts and injury reports. No FTN charting for this game (drops and interception-worthy throws are not modelled).

Methodology and validation · All Week 2 2021 games · Cowboys · Chargers

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