The backward pass.
With the 49ers trailing 24-21 with 5:08 remaining and the ball at the Packers' 44 yard-line, Garoppolo dropped back as the 49ers set up for a screen. The running back was held up and when the pressure got to Garoppolo, he tried to throw the ball away, but instead ended up throwing the ball backward for a fumble.
The Packers jumped on the fumble and went on to kick a field goal to go up 27-21.
In a 30-28 loss, the three points the Packers got off the backward pass proved to be the difference. After the game, Garoppolo explained what happened on the curious sequence.
“We were trying to run a screen pass, running back got caught up in the line a little bit,” Garoppolo said. “I got caught between throwing it. I was trying to throw it away and a guy hit my arm. Unfortunate call there by the ref for a fumble.”
Head coach Kyle Shanahan further explained that a lack of execution led to the early pressure on Garoppolo, which caused the backward pass.
"I thought Jimmy played real well tonight," Shanahan said. "The fumble there, it was a screen and he got let through way too early. It was a play-action screen and when he turned around someone was right in his face, and he tried to get rid of it and he threw it backwards."
After the Packers extended their lead to 27-21 following the fumble, Garoppolo led the 49ers on an eight-play, 75-yard drive which was capped off by a 12-yard to Kyle Juszczyk for a go-ahead touchdown.
But the 49ers left Aaron Rodgers 37 seconds too many, and the Packers quarterback threw two bullets to get Green Bay into field-goal range and Mason Crosby banged through a 51-yard attempt to hand the 49ers their first loss.
"Well, you're always conscious of [the clock]," Garoppolo said. "In that situation, there's a lot of different things going on. But yeah, game clock, you're always trying to get it as low as you can. It's just tough when you've got a guy like Aaron on the other side. You leave him any amount of time, you never know what can happen. I mean, the dude did it in 36, 37 seconds. You've got to tip your hat to him sometimes."