Sysyphus
Talk Tennis Guru
It's not mental, if it was, Federer would have problems with a lot more guys than Nadal. Rafa's game is just way too physical for Fed over long matches. It may have become mental after a while, but that's not why it's hard for him to beat Nadal. The same way Djokovic is really the only guy that can get in Nadal's head... at the end of the day it's because his game itself is the only one that can cause Nadal to get out of his comfort zone on a regular basis. The same is true for Nadal with Federer, his style doesn't let Fed do what he wants.
While I agree that match-up dynamics and game style is what affects this the most, the bolded is a completely unfounded inference. That people can have mental blocks or fears connected to very specific things but not to other similar things, is psychology abc. I find it hard to deny that the mental aspect plays a slight part in the match-up, even though it is not the dominating factor, especially given the extent of the game that sits between the ears.