World No. 1 Novak Djokovic says the three-way rivalry between Rafael Nadal, Roger Federer and himself is far from over as the trio prepares to battle it out at the US Open. The 24-year-old Serbian goes into Flushing Meadows having beaten Nadal in all five of their meetings this season, and has won three of his four clashes with Federer this year. His only defeat to the Swiss was in the semi-final at Roland Garros, Paris. “Both of them are playing incredible tennis still. Even though maybe Roger didn’t have the year as successful as he had in the past five, six years, I still think he’s playing really well. “I’m sure he is very much motivated to come back to the No. 1 in the world. Out of all of us, he knows best how to win the major events because he’s the record holder. He has 16 Grand Slams, has a fantastic career, and so I’m sure he wants to come back there. “Rafa is an unbelievable player, who is very complete and can perform equally well on all surfaces. He has proven that. We have played in five finals this year. I got the edge in all those matches, but that doesn’t mean that I will win every single match that we play in. The fact is that they have been the two most dominant players in the world. Even though I’m still No. 1, they are the two most successful players that there are active in today’s tennis,” said Djokovic. The Belgrade native is looking to win his third Grand Slam title of a remarkable personal season. He has lost just two matches in an eight-month span that has seen him win nine tour-level titles, including the Australian Open (beat Murray) and Wimbledon (beat Nadal).