Week 3 2021 · September 26, 2021
No FTN charting for this game (drops and interception-worthy throws are not modelled).
Packers at 49ers, Week 3 2021: who deserved to win?
The Packers beat the 49ers 30–28, and it was no fluke: replayed with the way both teams actually played, the Packers win 9 of 10. The 49ers had the bounces: judgment calls alone were worth 38 points of win probability to the 49ers.
An off day for the 49ers: they played far below what the matchup promised. In a fresh game against the Packers they would win 57% of the time; with this day’s form, 12%. The numbers
Before kickoff the 49ers were 60% favorites. The biggest swing (Q4, 0:03 left): M. Crosby made 51-yard field goal, worth 34 points of win probability to the Packers.
Final
 Green Bay Packers | 30 |
|---|---|
 San Francisco 49ers | 28 |
Replay with same day's form
Luck index +12 Packers about even · −12 49ers
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. Packers win 9, 49ers win 1.
- 1 GB 58 SF 24
- 2 GB 38 SF 13
- 3 GB 55 SF 34
- 4 GB 34 SF 17
- 5 GB 24 SF 10
- 6 GB 31 SF 20
- 7 GB 32 SF 24
- 8 GB 17 SF 12
- 9 GB 29 SF 27
- 10 GB 27 SF 33
Three other ways to ask
Each answers a different question, so none of them replaces the replay above.
Before kickoff
The closing betting line, turned into a probability. What everyone knew before the game.
Same teams, fresh 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.
Only coin-flips re-rolled
Every kick, fumble bounce, drop, conversion and judgment call redrawn; everything else fixed. The narrowest view of luck.
An off day for the 49ers
They played far below what the matchup promised. In a fresh game against the Packers they would win 57% of the time; with this day’s form, 12%.
Same teams, fresh game
Replay with same day's form
45 points apart for the 49ers: the gap is how differently this game went from what the two teams usually are.
| Unit | This game | Usual level | Better or worse than usual |
|---|---|---|---|
| Packers offenseEPA per play gained | +0.12 | +0.24 | worse by 0.12 |
| Packers defenseEPA per play allowed | +0.20 | +0.14 | worse by 0.06 |
| 49ers offenseEPA per play gained | +0.20 | +0.14 | better by 0.05 |
| 49ers defenseEPA per play allowed | +0.12 | +0.06 | worse by 0.06 |
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
Packers win 88% of them, 49ers 12%, counting the 1% still level after regulation as half each. The line is what actually happened: Packers by 2.
Show as a table
| Final margin in the replays | Share of replays |
|---|---|
| Packers by 17+ | 45.9% |
| Packers by 9–16 | 22.2% |
| Packers by 1–8 | 19.1% |
| Level after regulation | 1.4% |
| 49ers by 1–8 | 7.7% |
| 49ers by 9–16 | 2.7% |
| 49ers by 17+ | 1.1% |
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.
The kicks
How likely each kicker was to make that kick (his own record, the distance and the weather), and what happened.
- M. Crosby, 54 yds made · 62% expected
- M. Crosby, 38 yds made · 89% expected
- M. Crosby, 51 yds made · 68% expected
Penalties: Packers 7 for 87 yards, 49ers 4 for 86 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 toward luck, pre-snap fouls mostly don’t. How calls are valued
| When | Flag | Win probability for |
|---|---|---|
| Q1 12:00 | Face Mask on the Packers, 15 yards | +4% SF +1.6 pts |
| Q1 0:42 | Defensive Pass Interference on the 49ers (Deommodore Lenoir), 25 yards | +6% GB +2.5 pts |
| Q2 5:01 | Delay of Game on the 49ers, 5 yards · pre-snap | 0% GB +1.0 pts |
| Q2 4:00 | Defensive Pass Interference on the 49ers, 32 yards | +5% GB +2.8 pts |
| Q2 1:11 | Delay of Game on the Packers, 5 yards · pre-snap | 0% SF +1.0 pts |
| Q2 0:22 | Defensive Pass Interference on the Packers (Eric Stokes), 5 yards | +5% SF +1.8 pts |
| Q3 0:10 | Defensive Pass Interference on the 49ers (Fred Warner), 24 yards | +9% GB +2.6 pts |
| Q4 11:54 | Defensive Pass Interference on the Packers (Eric Stokes), 35 yards | +7% SF +4.2 pts |
| Q4 7:57 | Defensive Holding on the Packers, 2 yards | +2% SF +0.7 pts |
| Q4 6:39 | Roughing the Passer on the Packers (Jaire Alexander), 15 yards | +10% SF +2.6 pts |
| Q4 5:32 | Tripping on the Packers (Adrian Amos), 10 yards, wiping out the play | +18% SF +3.1 pts |
Packers penalties, every game · 49ers penalties, every game · All teams, 2021
When it happened
49ers’ chance of winning
As low as 0% and as high as 70%. Numbers mark the biggest luck moments, listed below.
| # | When | What happened | Win probability for | Next drive |
|---|---|---|---|---|
| 1 | Q1 13:54 | The Packers converted 3rd & 33rd & 4th downs · 54% expected | +13% GB | GB: Field goal |
| 2 | Q3 7:45 | The 49ers converted 3rd & 83rd & 4th downs · 24% expected | +10% SF | SF: Touchdown |
| 3 | Q4 5:32 | Tripping on the Packers (Adrian Amos), 10 yards, wiping out the playJudgment calls · 2 flags in 2505 snaps before, position avg 1 per 530 | +18% SF | SF: Turnover |
| 4 | Q4 5:08 | The 49ers fumbled and the Packers recoveredFumble bounces · loose balls are close to 50/50 | +15% GB | SF: Touchdown |
| 5 | Q4 2:29 | The 49ers converted 3rd & 103rd & 4th downs · 26% expected | +16% SF | SF: Touchdown |
| 6 | Q4 1:53 | The 49ers converted 3rd & 103rd & 4th downs · 27% expected | +19% SF | SF: Touchdown |
| 7 | Q4 0:16 | The Packers converted 3rd & 103rd & 4th downs · 29% expected | +29% GB | GB: Field goal |
| 8 | Q4 0:03 | M. Crosby made 51-yard field goalKicks · 68% expected for him, 11 of 13 from 45+ before | +34% GB | – |
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.
- Jason Verrett (SF CB), out (IR) · 0.4 pts
- Dre Greenlaw (SF LB), out (IR) · 0.3 pts
- Richie James (SF WR), out (IR) · 0.3 pts
- Tarvarius Moore (SF DB), out (IR) · 0.3 pts
- Kevin Givens (SF DL), out (IR) · 0.3 pts
- Elijah Mitchell (SF RB), out · 0.1 pts
- David Bakhtiari (GB T), out (IR) · 1.4 pts
- Elgton Jenkins (GB G), out · 0.5 pts
- Kevin King (GB CB), out · 0.4 pts
- Za'Darius Smith (GB LB), out (IR) · 0.4 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
Packers 77% · 49ers 23%
- Final margin
- Packers by 2
- Luck in points
- 6.2 for the 49ers
- Luck-adjusted margin
- Packers by 8.2
- Replay with same day's form
- Packers 88% · 49ers 12% unchanged: why
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 3 2021 games · 
Packers · 
49ers
More from Week 3 2021
- Panthers at Texans CAR 24–9 · replay 75% for the winner
- Cardinals at Jaguars ARI 31–19 · replay 91% for the winner
- Falcons at Giants ATL 17–14 · replay 64% for the winner
- Ravens at Lions BAL 19–17 · replay 52% for the winner
- Bears at Browns CLE 26–6 · replay 96% for the winner
- Bengals at Steelers CIN 24–10 · replay 85% for the winner
- Colts at Titans TEN 25–16 · replay 62% for the winner
- Chargers at Chiefs LAC 30–24 · replay 37% for the winner
- Saints at Patriots NO 28–13 · replay 83% for the winner
- Washington at Bills BUF 43–21 · replay 97% for the winner
- Dolphins at Raiders LV 31–28 · replay 92% for the winner
- Jets at Broncos DEN 26–0 · replay 95% for the winner
- Seahawks at Vikings MIN 30–17 · replay 42% for the winner
- Buccaneers at Rams LA 34–24 · replay 34% for the winner
- Eagles at Cowboys DAL 41–21 · replay 74% for the winner