Kind of, she says she's a vegan but cheats on the diet occasionally (with what i dont know but it doesn't really matter). However, it is better than nothing and if it gives a bit of publicity to the athletic viability of veganism, im okay with it (plus she doesn't pretend or hide the fact that she hasn't stuck 100% to veganism).
I think there was another vegetarian or vegan tennis player Navartilova but i think she occasionally ate fish or something.
For some reason it does seem like pros in other sports are going vegan a bit more than tennis, maybe its just my perception or something.
Also, not really relevant but Roger Federer was vegetarian from birth to 16 (or at least a young age)
"The best climber in the world is the one having the most fun"