How does tennis relate to the third law of motion?

I'm doing a science project on the physics of tennis and I can't find a way to word everything right so I was wondering if someone could explain to me how tennis is related to the third law of motion. Thanks.How does tennis relate to the third law of motion?Paraphrased, I believe Newton's Third Law is centered on



"For every action there is an equal and opposite reaction"



For instance, if you are leaning on a wall, you are exerting a force on the wall, also the wall is exerting a force on you. Propping you up. You would fall through the wall other wise. Apply that to your tennis racket.