Look at Nadal's record on indoor courts where he only plays once or twice a year, but are really the only exposure he gets to low bouncing, faster courts. .... Federer is obviously excellent on these courts as well, but not as good as he is on faster, low bouncing courts.
That court in London is really strange. I heard the commentators saying it was one of the slowest hard courts they've ever seen, one said it was slower than typical clay.
But the bounce is low. (Don't even know how that's possible)
Makes sense though in explaining Nadal's problems there. He hits the ball very hard, much harder than Federer, whose weapon is more placement. On the slow court, Nadal can't generate that kind of power.
With the low bounce, he can't make the ball get up with his vicious top spin to make even routine groundstrokes a little more troublesome for his opponent.
Its perfect for Fed. Placement makes life hard regardless of pace, and the vulnerability of his one handed back hand is negated by the low bounce, leaving just the extra reach and scope to create angles on that wing.