These two have already done all of that against each other and Djokovic is only 26, while Nadal is only 27, meaning we still have several years left in this rivalry. The two could finish with well over 50 matches between each other, considering that they have played 16 times in just the last three years.
The battle for year-end No. 1 in 2014 is a two-horse race. Nobody besides Djokovic and Nadal have a chance to finish the year at No. 1. The two dominate the tour right now. They combined for three of the four slams in 2013 along with eight of the nine 1000 events and the year-end finals. There is no reason it will be any different in 2014. Del Potro and Murray will try to break into the that top two, but their combined ranking in 2013 wasn't as much as either Nadal or Djokovic.
The more Djokovic and Nadal dominate the tour in 2014, the more times they will play each other. Since they are the top two players in the world, they will never play each other before a final, so they have to dominate the tour to play each another six more times.
In their six meetings in 2013, they split the two on clay and the four on hard courts. Unlike Fedal, Rafole is a rivalry on all surfaces. With that, a meeting between Djokovic and Nadal in the Roland Garros final could cement this rivalry as the greatest of all time. The pair's first meeting was at Roland Garros and it would be their third consecutive meeting at the second slam of the year. If Djokovic wins, it will give him a calendar slam with wins against Nadal in finals of all four grand slam events.
The one thing left that the rivalry needs to settle all debate would be a Davis Cup epic. Both players usually participate in Davis Cup and their countries are on opposite sides of the draw in 2014. What better way to end the year than with a Davis Cup match between Djokovic and Nadal. It wouldn't be a stretch to see Spain and Serbia in the Davis Cup final. Both countries reached the final once in the last two years. Djokovic and Nadal would meet in the fourth rubber, which obviously would have huge implications in determining the winner of the tie.