Nadal responded to Federer's strategy of attacking returns by serving much more aggressive. You don't have much of Federer asserting the chip and charge against those serves. The other thing to note is how Federer is not crowding the baseline in these rallies. It is true that Federer had the better tempo at the beginning and Nadal weathers the storm like he usually does. Federer even had break point to win the first set. But his backhand in the first tie breaker appeared to be shaky towards the end under pressure. He is not staying as adamantly turned nor ripping those short backhand crosscourts.
Federer doesn't come into the net much here with the same frequency and insistence as the 2010 Masters final. He is then susceptible to Nadal slinging his forehand around, forcing Federer to cover the corners, dictating the points. It is interesting to see Federer do some midcourt stuff, but with Nadal serving heat and hitting those monster forehand crosscourt drives, the winning advantage is to Nadal in two tiebreakers.