My yoga teacher taught me that "have fire in my belly but cool running water in my head". This system works very well on the court!
Having 🔥: being tenacious - passionate - committed - trying your best - going for it!
And ❄️: peaceful - focused - allowing - contained - calm - accepting - in flow!
A well balanced tennis player is able to let go of each point - and the match - as soon as it's completed - learning the lessons but moving on!