When you, as a tennis player, focus too much on victory, you are distracting yourself from what you have to do to get the desired result. Of course, this does not mean you cannot be aware of your desired results, or visualize those results in your mind. But it does mean that you should not overly obsess over those results. Having result expectations means focusing on the outcome we expect. We must balance the desire for good results with a focus on the match at hand, which needs to be won in order to produce a good result. If we believe that things will work out, we can undertake a match or tournament with a positive and confident attitude. In other words, we must expect a positive result. On the contrary, if we foresee a difficult situation, our attitude will be influenced by this conviction and we will act accordingly, often creating the expected outcome.
It's a bit like the difference between those who see the glass half full and half empty: they are two different ways of seeing the same situation. The difference is not in the glass of water, but in the minds of those who look at it. If you see the glass half full, you will see the world in a certain way, and realize the opportunities offered by every situation.
Let’s consider this from a tennis perspective.