I watched most of the game and I still can't believe the Giants won. They got killed in yardage, only 230 total yards to Dallas' 336, and time of possession, 23 minutes to Dallas' 37. Early in the game, Dallas' offensive line was in control and RB Marion Barber ran with ease. The Giants had a lot of trouble getting pressure on QB Tony Romo for most of the game.
But Dallas had to score on drives of over 90 yards on both of their touchdowns and the Giants made them slowly work the length of the field consuming over 15 minutes. Dallas couldn't take advantage of the backup secondary playing in place of the injured starters. The 11 penalties for 84 yards hurt Dallas, and the 25 yard punt return by CB R.W. McQuarters was a big play. But in the end there were two big keys to the game.
First was the Giants offense was able to sustain three scoring drives. That seems kind of obvious but what I'm getting at is that Dallas had the ball for so long that the Giants only had possession eight times during the game. When the Giants defense really needed the offense to get some first downs and keep the ball in the 4th quarter, the Giants only managed 11 yards and two punts, giving Dallas multiple chances to win the game. Although the Giants' offense only gained 230 yards, they had 185 yards on their 3 TD drives. When they were able to put it all together, they drove for a TD.
Second was Dallas offense became one dimensional in the fourth quarter. Barber ran for 101 yards in the first half and only 26 in the second half, due in part to improved play by the Giants defense, but Dallas' offensive coordinator Jason Garrett got pass happy once Dallas went down 21-17 and gave Barber few chances, although the Giants scored their last TD at the start of the 4th quarter and Dallas had an entire quarter to get the lead back. Plenty of time to run and pass the ball. The Giants pass rush was much better in the 4th quarter and seeing that nearly every play called was a pass had to help them knowing that they didn't have to account for Barber.