Some aspects from the book, very close to my notices:
"The thought of losing doesn’t bother me now. It only bothers me if I haven’t given 100-percent
effort. So the pressure is off. If I lose, I lose. I now know that if I stay positive and keep
working, my talent will eventually come out.
Being a mentally tough competitor means controlling how you feel inside. Three primary
strategies accomplish that. The first is controlling what you think; the second is controlling
what you visualize; the third is controlling how you look on the outside, in short, your physical
presence. Make a commitment to improve your physical image every time you play or practice your
sport. Improve your walk, your appearance of intensity, and your look of aggressiveness. Athletes
rarely, if ever, train in this area, yet my experience reveals its importance in building mental
toughness.
One reason why we outwardly display negative emotions is to let everyone around us,
including our opponent, know that we’re really much better than we’re playing. We want them
to know that we’re “off” and are capable of much more. “If I don’t show I’m upset, they’ll think
that’s how I play all the time.” That strategy may appear to save your ego or pride, but it will
eventually undermine you. Indeed, you rarely convince anyone, including your opponents,
and you end up locking in the negative feelings. You continue to feel precisely like you act –
miserable, upset, and negative. The performance consequences of those feelings are clear.
Furthermore, when an athlete acts negatively, he often raises the confidence level of his
opponents."
Counting points and focusing on score makes your ego to focus on what YOU need. You better focus on what the Ball needs. Even the best top players sometimes lose their 5 match points with the confidence that they've done what they need. And on the opposite - well concetrated on the Ball players with strong psychics can come back and turn over and win.
About physical, psychological and emotional shape - its very well stated above.