These battles are mostly mental.... These guys put tremendous pressure on each other, knowing any easy serve, easy groundtsorke can be punished and knowing they need to red line since both are great defenders. Nadal made uncharacteristic # of double faults and that volley miss was crazy... but it was tightness IMO. Rafa started unbelievably strong, dominating Novak... Novak felt the pressure and he himself had some letdowns. Novak then started to, very deliberately, attack Nadal's bh and things started to become more difficult.. i could sense Nadal was getting frustrated and started to miss more shots than he usually does... but it's not as easy as to say 'he just played bad'... it was high quality and a mental battle which even gets to them.