Rafael Nadal vs Roger Federer
As their epic Wimbledon final demonstrated Roger Federer and Rafael Nadal are locked in a desperate battle to be the No.1 tennis player in the world. Major finals involving these two men are a common occurrence as Nadal appears to be the only player in the world capable of challenging Federer's near omnipotent dominance of the sport.
While this is a rivalry built on professional competitiveness rather than personal dislike it is no less intense. Each man is driven by a near obsessive desire to be the best and as the Wimbledon final showed it brings the best out of them forcing them to raise their game, which can only be good for spectators.