She wants to get even with the guy who hit her with the ball.
Related vocabulary: settle a score, stick it to someone
get even with
To exact revenge on someone. This prank may seem elaborate, but I need to get even with my brother for dumping a bucket of water on me the other day.Sheila swore that she would get even with me after she figured out that I had started the rumor about her.
get (or be) even with
inflict similar trouble or harm on someone as they have inflicted on you. informal
be/get ˈeven with somebody
(informal) cause somebody the same amount of trouble or harm as they have caused you: I’ll get even with him some day for making those nasty comments about me.