luckadjusted
NFL Week 9 · 2026

Week 1 2023 · September 10, 2023

49ers at Steelers, Week 1 2023: who deserved to win?

The 49ers beat the Steelers 30–7, and the replays lean their way: with the same day's form, they win 7 of 10.

Before kickoff the 49ers were 54% favorites.

Final

San Francisco 49ers 30
Pittsburgh Steelers 7

September 10, 2023 · Acrisure Stadium · Closing line: 49ers −1.5

Luck index +29 49ers lucky · −29 Steelers

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. 49ers win 7, Steelers win 3.

  1. 1 SF 34 PIT 6
  2. 2 SF 41 PIT 20
  3. 3 SF 38 PIT 23
  4. 4 SF 28 PIT 17
  5. 5 SF 35 PIT 27
  6. 6 SF 23 PIT 18
  7. 7 SF 12 PIT 10
  8. 8 SF 17 PIT 20
  9. 9 SF 13 PIT 20
  10. 10 SF 14 PIT 30

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

49ers win 71% of them, Steelers 29%, counting the 4% still level after regulation as half each. The line is what actually happened: 49ers by 23.

Show as a table
Final margin in the replaysShare of replays
49ers by 17+24.7%
49ers by 9–1620.0%
49ers by 1–824.4%
Level after regulation3.8%
Steelers by 1–815.0%
Steelers by 9–168.0%
Steelers by 17+4.1%

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 +3.1 points to the 49ers: the final margin was 49ers by 23, without the luck 49ers by 19.9. 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.

  • J. Moody, 41 yds made · 86% expected
  • J. Moody, 32 yds made · 95% expected
  • J. Moody, 40 yds made · 88% expected
Bar: expected chance of a make. Filled dot: made. Open dot: missed or blocked.

Penalties: 49ers 11 for 85 yards, Steelers 6 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 9:29 Delay of Game on the 49ers, 5 yards · pre-snap 0% PIT 0.0 pts
Q1 6:38 Offensive Holding on the 49ers, 10 yards +2% PIT +1.3 pts
Q1 4:48 Defensive Offside on the Steelers (Patrick Peterson), 5 yards, wiping out the play · pre-snap +3% PIT +1.0 pts
Q1 3:16 False Start on the Steelers (Elandon Roberts), 5 yards · pre-snap +1% SF +0.4 pts
Q1 0:06 False Start on the 49ers, 5 yards · pre-snap +1% PIT +0.6 pts
Q2 13:05 False Start on the Steelers, 5 yards · pre-snap +1% SF +0.4 pts
Q2 12:30 Face Mask on the Steelers, 15 yards +2% SF +1.4 pts
Q2 12:17 Illegal Motion on the 49ers (Deebo Samuel), 5 yards · pre-snap 0% SF +0.6 pts
Q2 10:32 Unnecessary Roughness on the Steelers (Levi Wallace), 15 yards +2% SF +1.8 pts
Q2 1:50 False Start on the 49ers, 5 yards · pre-snap +1% PIT +0.4 pts
Q2 1:24 Unnecessary Roughness on the 49ers (Deommodore Lenoir), 15 yards +1% PIT +1.7 pts
Q2 0:18 Illegal Contact on the 49ers (Deommodore Lenoir), 4 yards +2% PIT +1.0 pts
Q3 7:14 False Start on the 49ers (Samuel Womack), 5 yards · pre-snap 0% PIT +0.1 pts
Q3 5:42 Face Mask on the 49ers, 15 yards +1% PIT +1.4 pts
Q3 4:53 Defensive Pass Interference on the 49ers, 11 yards +1% PIT +1.2 pts
Q4 10:23 Illegal Forward Pass on the 49ers (Talanoa Hufanga), 5 yards 0% PIT +0.5 pts
Q4 5:01 Unnecessary Roughness on the Steelers (George Pickens), 15 yards +1% SF +1.0 pts

49ers penalties, every game · Steelers penalties, every game · All teams, 2023

When it happened

Steelers’ chance of winning

As low as 0% and as high as 55%. 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 Steelers were ahead in it, below while the 49ers were.
#WhenWhat happenedWin probability forNext drive
1 Q1 14:02 The Steelers were stopped on 3rd & 53rd & 4th downs · 42% expected +4% SF PIT: Punt
2 Q1 12:09 The 49ers were stopped on 3rd & 13rd & 4th downs · 76% expected +4% PIT SF: Touchdown
3 Q1 11:34 The 49ers converted 4th & 13rd & 4th downs · 76% expected +5% SF SF: Touchdown
4 Q1 8:08 The Steelers threw an interception-worthy pass, and it was pickedInterceptions · defenses catch 50% of interception-worthy throws +4% SF PIT: Punt
5 Q1 5:32 The 49ers were stopped on 3rd & 143rd & 4th downs · 24% expected +3% PIT SF: Field goal
6 Q1 4:48 Defensive Offside on the Steelers (Patrick Peterson), 5 yards, wiping out the playPre-snap flags · 24 flags in 4149 snaps before, position avg 1 per 216 +3% PIT SF: Field goal
7 Q1 3:05 The 49ers fumbled and recovered it themselvesFumble bounces · loose balls are close to 50/50 +4% SF SF: Touchdown
8 Q1 2:01 The 49ers got away with an interception-worthy throwInterceptions · defenses catch 50% of interception-worthy throws +4% SF SF: Touchdown

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

49ers 100% · Steelers 0%

Final margin
49ers by 23
Luck in points
3.1 for the 49ers
Luck-adjusted margin
49ers by 19.9
Replay with same day's form
49ers 71% · Steelers 29% 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 2023 games · 49ers · Steelers

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