response: I don't know!  I do know that he is widely considered to be the greatest clay court player ever.
original_response: I think all of his victories were great, I can't decide, they don't call him ''The King of Clay'' for nothing!
history: I think Rafael Nadal is the best tennis player of all time. What do you think? Oh Nadal?  Well he's won a lot of titles, tournaments and medals. What do you think was he's best grand slam victory ever?
knowledge: Known as ''The King of Clay'', he is widely regarded as the greatest clay-court player in history.