He didn't feel anything different between the playground and an elimination game in the NBA playoffs because he approached each day the same. This is where mental repeatability makes you a winner. Repetition leads to more rapid automation of your basketball skills. Automating your skills allows you to release attentional capacity to attend to more critical elements of the game, and to grow as a player in terms of your decision making ability. Repetition can demonstrate that you have the personal ability to listen, change and repeat.
All great players can listen, change quickly.
They are able to take a detail and switch a key decision or skill component as simply as you would change a fuse in a fuse box. When you can listen and change you are going to get playing time, I guarantee you. Coaches invest time in players who are quick learners. Repetition results in more consistent performances in practices and games. The best players in the game yesterday, today and well into the future are those who can consistently perform.