Originally Posted by timnz
The OP is completely right. The Federer Nadal head to head is completely and utterly about the surfaces they have played on.
Federer is better on Clay (his worst) than Nadal is indoor (his worst)... hence, in the 2000's Federer made far more finals on clay - and who did he meet in those Finals? Nadal of course (because it is his best surface). Unfortunately indoor tennis has moved from being one of the most important surfaces in the 80's and 90's to almost non-existent now - that also contributes to Federer and Nadal lack of matches against each other on that surface.
I always say to those who think Surface is irrelevant to head to head - Really? Do you think that Borg/McEnroe head to head would be the same if they had played all their matches on clay?
It's not just the surfaces. It's the styles. Nadal's style basically is designed to beat Federer. If you were to create the perfect player to expose Federer's weaknesses on paper, you'd literally come up with Nadal. A lefty topspin monster who hits 99% high bouncing backhands to the Federer one hander.