I doubt there has been a better match up in history between a player and a particular surface. Maybe Sampras and grass... Slams are obviously the most important titles in the game and competitive tennis is about titles. Still, Nadal's game is tailored for clay; even stripped from his titles and wins, the tennis he plays on clay is unmatched in my opinion. Borg is ahead of my time but one can still watch his matches, and I think Nadal is already ahead of him, at the very least he's not inferior.