回复：A simple question, did you ever understand

if you're questioning me how he could have picked up new techniques in tennis so fast;

I'd say thats why he is being called a talented top player that always can learn new stuff faster in a shorter period of time than normal people like you and me.

but if you have become skeptical about this guy's being under the influance of drug, you then need to provide readers some,if any, kind of evidence to make your doubts reasonable, otherwise, its absolutelly your own speculations or in other words; worthless illusions if not gossips.