Play and exercise are primal, so yes tennis is 'primal' ... but don't get so attached to the label, I think that doesn't usually end well.
I played tennis in HS (third singles, which is to say I was the third best player on the team, but that doesn't mean I was good, we were just all pretty bad) but I wasn't eating primal then. However, my diet in HS wasn't entirely terrible and I was always active so I didn't have issues with practice or games.
My worst memory is getting spanked by a kid in one of the richer towns we played against, I didn't win a single game, he beat me in straight sets and aced me almost every time he served. My entire team lost horribly though, those kids were probably playing since they were 3. In retrospect it's actually not such a bad memory after all, we were all laughing about it on the bus ride home, even our coach. I think we got ice cream, even though we were all well past that age, we just needed some up-lifting..