We haven’t had a chance to talk about how win probability shifts in a game because the San Francisco 49ers have largely played clean games during their six-game winning streak to start the season. That changed against the Atlanta Falcons, who forced four turnovers.
According to Next Gen Stats, the Falcons gained +41.8% win probability on the Niners’ four turnovers.
If sports have taught us anything, it’s that no lead is safe. San Francisco’s win probability peaked at 80% when they took a 14-3 lead after Kaelon Black’s 30-yard touchdown run to begin the game.
Even after Atlanta trimmed the lead to 14-9 in the second quarter, San Francisco still had a 73% win probability. That climbed back to the high 70s after Luke Farrell recovered Jordan James’ fumble.
Kaelon Black’s fumble dropped its win probability to 68%. One turnover shouldn’t kill you in a game where you’re bound to get double-digit possessions. The Falcons still needed to march over 70 yards to score.
For a brief moment, the Niners’ chances of winning rose to 70% on 4th and 4. The Falcons tacked on a field goal before the half. At 14-12 heading into halftime, San Francisco had a 57% chance to win.
Michael Penix completed an 11-yard pass to Austin Hooper on 2nd and 7. At 13:08 in the third quarter, the win probability split 50/50 for the first time. That was the first time it had been that way in the game.
When Penix found Drake London on 3rd & 7 for 10 yards against Jack Jones, the Niners dipped to 46%, dropping below 50% for the first time all game.
After the Falcons took the lead, the probability changed to 38%. It was 19-14 with nine minutes left in the third quarter. That’s an eternity.
After their third double-digit gain of the drive, the Niners were at Atlanta’s 35-yard line, with a 52% win probability. They lost 12 percentage points, dropping from 44% to 32% after Purdy’s interception on a target along the sideline.
The defense looked like they were going to get off the field and give the ball right back to the offense, but a penalty on 2nd and 20 and a 19-yard gain on 3rd and 3 swung the win probability 14% in two and a half minutes.
When the Falcons scored to make it 26-14 to begin the fourth quarter, their win probability was as high as 87%. The Niners’ hopes looked bleak, but they still had a chance.
After a touchdown and a forced punt, the Niners got the ball back with 4:08 left, and a 22% chance to win. But an interception with 2:42 left dropped the Niners’ win probability from 20% to 1%.
The swings were drastic in this game. Both sides had outlier performances. We haven’t seen multiple interceptions from Brock Purdy or fumbles from the running backs. It was the first time Atlanta has forced multiple turnovers all season.
It’s a loss that’ll be dissected all week since the 49ers have their bye, but they win if they hold onto the ball. It’s as simple as that.
The 49ers score a TD on 86% of their red zone trips. The Cowboys are second at 77%. Shanahan and Purdy have been excellent in the red zone this season. Once they get inside the 20, you’re as close to a guaranteed touchdown as you can get.
Purdy’s first interception was at Atlanta’s 25 on 2nd and 14. On the drive where James and Black fumbled, the 49ers had picked up 7, 10, and 11 yards leading up to those two plays. The offense had the ball at Atlanta’s 28.
Even if you remove the two fourth-quarter turnovers, you’re leaving 10-14 points off the board. That’s the difference in the game. Add in the probability of scoring on the two fourth-quarter drives, and it’s hard to poke holes in anything other than the turnover luck.