Not everyone's mind works the same way. Sports is not something you can perfect. The one's that accomplish the most apply themselves towards the pursuit of perfection. But they don't get paralyzed with the need to BE perfect. If that makes sense? You have to have a short memory in the heat of competition. Some players handle this fine until they reach a certain level of pressure. Everyone has a point where the amount of pressure exceeds their ability to perform the same. I'm talking about the mental game.
If I give you a baseball and ask you to throw a strike at a batters box on the gym wall, you could do it. If I give you the ball and ask you to bet $1000 on your ability to throw a strike, you might be able to do it. If I ask you to bet $100,000 on the throw, you can't do it. What's changed? Not the ball, the distance or the size of the target. The pressure.
Now replace the bet of money with the size of the crowd. Throwing a strike with nobody in the gym vs throwing a strike with 70,000 people watching is another thing entirely. 70,000 people that might boo you if you can't throw that strike.