When you feel good, you are apt to play well. Conversely, when you feel bad, you are likely to play poorly.
Sport psychologists talk about the need to control emotion on court, but what they mean by this is not simply suppressing emotions (like anger or depression). Instead they are talking about an optimum strategy by which players not only rid themselves of negative emotions but also work to create positive ones.
During tennis, as with other sports, positive emotions help but do not guarantee good play. This fact tends to confuse players because they often find that they still lose matches even after disciplining their emotions.They start to think emotional control has no value. And they are dead wrong! Even though good emotions do not ever guarantee a victory, bad emotions often guarantee a loss.
Emotions only set the stage for the quality of play that follows, but they don't control it. Good emotions only make good play more likely; they don't guarantee anything.
Finally, emotional effects on tennis performance are often overlooked because they may be small, sometimes only a difference of a point or two here and there, which are hardly noticeable. (But these few points, in a close match, often make the difference between winning and losing.)
Habits, Repetitions and Our Strokes
Our strokes are controlled by sequences of muscle memories that are programmed into the nervous system through repetition in practice. The more correct repetitions, the more accurate the programming and the more likely the stroke is to function properly in competition.
Optimal tactical responses to an opponent's shots during play are also programmed into our nervous systems by reward and punishment during past competition. For example, when we hit the right shot and win the point and, in the same situation, hit the wrong shot and lose the point, our nervous systems record this information and use it later to improve shot selection.
Eventually, the strokes and immediate tactical responses are no longer under conscious control in matches. They function by habit and come out too quickly for conscious thought.
Of course, at the conscious level, we need to have game plans and remain sensitive to how well they are working in order to make effective adjustments, but this is all superimposed upon the set of basic programmed habits and responses that function below the level of conscious thought.