Rafa is punishing him.
12:15 - Novak - After missing a high backhand down the line he looked up to the Gods or Clouds or whatever he was raising his hands to hoping to express his difficulties and frustration.
Rafa is seemingly implacable after a rough first set and then two strong sets that he took in a dominating form.
Mac is right when saying that Novak needs to become aggressive on the return. Just playing closer in and going on the attack would alter the equation and force Nadal to change his game.
As this is said, Novak played it safe on a two hander and then missed a forehand down the line that in normal time he wouldn't.