Tennis (and other interactive sports, like boxing) have a form of built-in randomness similar to rock paper scissors. Obviously not to the same level of randomness, but you both execute an action at the same time not knowing what the other person is going to do (although if your reflexes and awareness are higher, you're playing that RPS game faster than the other player).

An example that makes this element really obvious is turn-based fighting video game Toribash.