Peyton Manning and the Bronco's were ready to play an awesome Super Bowl against the Seattle Seahawks, but then something happened. Manning missed the first snap of the game.
As Lindsay H. Jones of USA Today Sports noted, "...the bad snap was the moment that seemed to change so much for Manning, who on Saturday night received his fifth NFL MVP award."
From a mental game perspective, I totally agree. A player can build themselves up, can psych themselves up, and their confidence can spread like a wave, affecting the other players on the team, as well.
But, when something unexpected happens (like a bad snap that costs the team), unless the player is able to dump that negative experience, it can derail them.
I believe that's what happened. It's kind of like a stack of cans, you pull out the right one, they all fall down. And the quarterback's attitude drives the team. If he starts second-guessing himself, or makes mistake after mistake, the team expects that it will all roll downhill and they will suffer, also.
Since it's impossible to anticipate every negative event, what *can* be done is to build a mechanism to let go of the emotional effect of mistakes, bad luck and anything else that's not directly related to moving the ball forward and scoring.
Then the player is in charge of their mental game and is not subject to being controlled by it.