Learning to play relaxed when the adrenaline is pumping through your body is one of the hardest things to do during competitions. That is a challenge that you will see the pros even struggle with sometimes.
Here are a few tips that may help you learn to play relaxed:
Make sure you loosen up your grip, shoulders, and legs before you serve or return.
Breathe out as you hit the ball.
The more you compete, the more you get use to that feeling of butterflies in your stomach!
When Novak Djokovic won one of his US Opens, he was 2 points away from losing the match to Roger Federer. Fed hit a great wide serve - but Djokovic was so loose that he ripped the return. He realized he nothing to lose at that point. Djokovic obviously won that match, and then went on to win the tournament. Staying loose for that one point and coming up with the shot of the tournament brought him the title.