Serena Williams would definitely defeat Roger Ebert...since Ebert is dead. She would lose to Roger Rabbit because he's animated and he's a rabbit so he can cover ground much faster and rabbits have even more fast twitch muscle fiber than Serena. Now if you are talking Roger Federer against Serena? The chances of Serena defeating Roger Federer in an actual tennis match is about the same as Roger Ebert defeating Serena Williams in a tennis match right now. So yes, this is a stupid question, far worse than the stupid MMA heads who thought Ronda Rousey had a shot at defeating 135lb UFC male fighters.