Of course - when we step out to play a match - we are doing our best to try to WIN the match - however I have noticed that if I have too much ATTACHMENT TO WINNING - I will not play my best!
You see - if my inner voice and ego are saying "you have to win this match" or "you are much better than the opponents" or other such pressure enduring stories - I play tight. I don't serve as well - my limbs stay closer to my body - and the fear of making mistakes makes me play hesitantly!
As we have seen with the professional players - as they became more centered - they have also had much more success!
Federer used to throw rackets! Look at him now! Cool as a cucumber!!! Learn from the best - play well - but enjoy the journey - then - whether you won or lose - you still had FUN!!! (Plus it's easier on your partner too)!!!