I think there’s a guy at my badminton gym who is trying to bully me and my friend. Is it physical assault, and how should I respond to hold him accountable?

I 27M play badminton at a gym each week. A new guy named Presley (28M; not his real name) showed up; him and I were the first four people to step onto the court, so I offered to play a badminton doubles game with him against two others that were also there - we were the first four to show up and our skill level was similar, so it made sense.

Then, a regular badminton player named O (29F) shows up, and Presley immediately claims that “I don’t want to bully you guys, but O was there [before me] and therefore I should get to play with O instead”. O and the other two people there deny this (she was clearly one of the last to arrive) so we go ahead and proceed with a 2v2 match: me and Presley vs players 3 and 4.

During the match, Presley was whacking my butt with his racket between rallies. While it wasn’t hard enough to hurt much, it felt very weird and my butt ended up with a red racket mark when I got home. O also told me that when she played a badminton game with Presley, he hit her butt too.

Isn’t this physical assault? We live in California. I took a selfie of my butt but the mark is very light and will probably go away tomorrow, and the idea of showing the photo to the police seems kind of embarrassing to me. I’m also afraid he may go after the elderly badminton players that I carpool with as revenge. What should I do?