Much of the focus will be on Sam Shields' interception of Tony Romo that led to Green Bay's winning score. Facing second and 6 from the Dallas 35, Romo did not carry out the running play because he felt the Packers overloaded the right side of the Cowboys’ formation and threw a "smoke" to Miles Austin.
Let’s look at that play.
The Cowboys were in 12 personnel with two tight ends and DeMarco Murray. They are in the same formation as they were in when they ran their first play of the game. That play netted them 11 yards on a Murray carry.
But there were some differences in how this play was run.
On the first play, Gavin Escobar, who is in a bunch formation with Jason Witten and Austin, motions to the weak side. He blocks outside linebacker Clay Matthews with the run going to the strong side. Escobar just has to get in the way of Matthews, not really block him with any kind of power.
Witten does a great job with his block on Nick Perry. Doug Free and Mackenzy Bernadeau chew up the line and linebackers, which gives Murray a nice gain. The safeties were not in the screen shot on the TV copy and the Packers had seven in the box. Cornerback Tramon Williams is lined up eight yards off of Austin.
Clearly this is the same play as the first snap.
Listening to the television copy of the game, you can hear Romo put his hand up and say, "Stay."
Since Escobar did not go in motion on the play, as he did on the first snap, we can surmise Romo is talking to him. We know Bill Callahan called a running play here. And on the first play of the game you can hear Romo end that play call with the word "smoke," as they break the huddle, so we know that option was there, too.
Romo has decided to throw to Austin because the Packers' deepest defenders are only six yards off the line of scrimmage. Safety Morgan Burnett has flipped spots with cornerback and is lined up outside Williams but close to the box, only three yards off the ball.
Without motioning Escobar, Matthews is left unblocked. There is no play-fake to Murray for Matthews to read. At the snap he breaks to Romo and somehow misses the sure sack. Escobar attempts to move from the strong side to pick up Matthews but it would be impossible for him to block him.
Austin ran a great route and turned Shields around off the jam. There is space for a big play. But Romo's momentum after getting away from Matthews is taking him to his left and as a result his pass to Austin is behind the receiver and gives the trailing Shields the chance for the interception.
Were the Packers prepared for the run? Sure. Should the Cowboys have run it anyway? Absolutely.