Some features determine who is winners (Sorry bad drawing, I don't know how to use computer drawing software). 1. Good Return
Many of Djokovic's return drop in the middle of the court with good deep. Nadal always has tourble with this return. No time for him to set up and it force him to hit short ball. Also, this reutrn does not give Nadal any angel. Djokovic return well , especially second serve. He see the chance and go for winner. 2. Baseline rally
It is very interesting to see how Djokovic deliver the ball on the court. He deliver the ball to Nadal's backhand and move Nadal to right concorn, and wait for right moment for the forehand down the line. For most time, Nadal is chasing that forehand down the line. If Nadal can get the ball and make the shot. No worry, Djokovic has backhand down the line. Then Nadal chase the ball again. In entire match, Djokovic do it again and again, move Nadal away baseline rally. Also, Djokovic does not make big shot. It is his routine groundstroke shot.
If Nadal still can get ball back, then cross court backhand and use the same tactic again.
3. Slice serve
Djokovic serve some slice serve to Nadal's backhand which very effective. Gain short return and make volley to other direction which alway move away. However, sometime he choose wrong direction cause himself by passing shot.
My consideration is it is all about good return to set up point. Because these good reuturns allow Djokovic from start to the end in many point by using this tactic. So I said that Nadal has to keep his 1st serve percentage high to get short return and cheap point. The poor 2nd serve win percentage prove my theory.