1. Atlanta's road loss to New Orleans
This was the first hint that Atlanta's season could tilt in the wrong direction. The Falcons had a perfect division record and were looking to move to 5-0 within the division giving themselves a huge cushion. Win this game and you're going to be able to coast the rest of the season. New Orleans was on a losing streak and had just fired head coach Dennis Allen. Atlanta only needed to get to 21 points to win this game and continually Cousins made mistakes.
Atlanta's first hint that the quarterback running out of gas was in this game. Kirk's turnovers and lack of confidence were glaring with the Saints begging the Falcons to take control of this game. Over and over the Falcons were handed the ball needing just one drive to put themselves back in control and survive the worst offensive game of the season.
These are the type of games in which true playoff teams won't fumble away. Even when things are ugly and the team is in their own way, one final drive gets the job done. Atlanta was unable to do this and would be blown off the field in Denver the very next week.