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).

Vikings at Cardinals, Week 2 2021: who deserved to win?

The Cardinals beat the Vikings 34–33, and the replays lean their way: with the same day's form, they win 7 of 10. The Vikings had the bounces: fumble bounces alone were worth 9 points of win probability to the Vikings.

Before kickoff the Cardinals were 62% favorites. The game turned on a luck play (Q4, 0:04 left): G. Joseph missed a 37-yard field goal, worth 76 points of win probability to the Cardinals.

Final

Minnesota Vikings 33
Arizona Cardinals 34

September 19, 2021 · State Farm Stadium · Closing line: Cardinals −4

Luck index +28 Cardinals lucky · −28 Vikings

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. Vikings win 3, Cardinals win 7.

  1. 1 MIN 34 ARI 14
  2. 2 MIN 33 ARI 24
  3. 3 MIN 40 ARI 37
  4. 4 MIN 31 ARI 33
  5. 5 MIN 31 ARI 36
  6. 6 MIN 16 ARI 24
  7. 7 MIN 24 ARI 37
  8. 8 MIN 7 ARI 24
  9. 9 MIN 13 ARI 34
  10. 10 MIN 6 ARI 37

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

Vikings win 28% of them, Cardinals 72%, counting the 3% still level after regulation as half each. The line is what actually happened: Cardinals by 1.

Show as a table
Final margin in the replaysShare of replays
Vikings by 17+5.5%
Vikings by 9–168.1%
Vikings by 1–814.0%
Level after regulation3.4%
Cardinals by 1–822.5%
Cardinals by 9–1619.4%
Cardinals by 17+27.2%

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 +3.7 points to the Cardinals: the final margin was Cardinals by 1, without the luck Vikings by 2.7. 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.

  • G. Joseph, 52 yds made · 71% expected
  • M. Prater, 62 yds made · 48% expected
  • G. Joseph, 52 yds made · 72% expected
  • M. Prater, 27 yds made · 97% expected
  • G. Joseph, 37 yds missed · 93% expected
  • Extra point missed · 94% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: Vikings 3 for 16 yards, Cardinals 5 for 40 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 13:08 False Start on the Cardinals, 5 yards · pre-snap +3% MIN +1.3 pts
Q1 12:55 False Start on the Cardinals, 5 yards · pre-snap 0% ARI +0.4 pts
Q2 3:49 Offensive Holding on the Cardinals (A.J. Green), 10 yards +2% MIN +0.8 pts
Q3 7:44 False Start on the Vikings, 5 yards · pre-snap +3% ARI +0.7 pts
Q3 2:42 Roughing the Kicker on the Cardinals (Tanner Vallejo), 15 yards, wiping out the play +7% MIN +2.6 pts
Q4 10:23 False Start on the Vikings (Ben Ellefson), 1 yard · pre-snap +2% ARI +0.6 pts
Q4 8:51 Ineligible Downfield Pass on the Cardinals, 5 yards +4% MIN +0.7 pts
Q4 4:25 Offensive Holding on the Vikings, 10 yards +8% ARI +1.2 pts

Vikings penalties, every game · Cardinals penalties, every game · All teams, 2021

When it happened

Cardinals’ chance of winning

As low as 16% and as high as 100%. 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 Cardinals were ahead in it, below while the Vikings were.
#WhenWhat happenedWin probability forNext drive
1 Q1 5:57 The Cardinals converted 3rd & 103rd & 4th downs · 29% expected +9% ARI ARI: Touchdown
2 Q3 14:09 Return touchdown by the VikingsSpecial teams +31% MIN MIN: Opp touchdown
3 Q3 1:50 The Vikings converted 3rd & 103rd & 4th downs · 31% expected +13% MIN MIN: Field goal
4 Q4 6:12 The Cardinals converted 4th & 53rd & 4th downs · 44% expected +18% ARI ARI: Field goal
5 Q4 4:25 Offensive Holding on the Vikings, 10 yardsJudgment calls +8% ARI ARI: Punt
6 Q4 2:56 The Vikings were stopped on 3rd & 63rd & 4th downs · 41% expected +8% ARI MIN: Punt
7 Q4 1:21 The Vikings converted 3rd & 103rd & 4th downs · 31% expected +19% MIN MIN: Missed field goal
8 Q4 0:04 The game turned hereG. Joseph missed a 37-yard field goalKicks · 93% expected for him +76% ARI –

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

Vikings 72% · Cardinals 28%

Final margin
Cardinals by 1
Luck in points
3.7 for the Cardinals
Luck-adjusted margin
Vikings by 2.7
Replay with same day's form
Vikings 28% · Cardinals 72% 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 · Vikings · Cardinals

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