Rafael Nadal and Novak Djokovic, alonsgide Roger Federer, are considered among the greatest tennis of all time. But who is the best? Former World No. 2 picks and explains his choice.

MELBOURNE, Australia -- And then there was one: The Big Three is down to just Novak Djokovic, who stands alone from a golden generation of men’s tennis now that Rafael Nadal has joined Roger Federer in retirement.

Novak Djokovic has broken another monumental record, becoming the player with the most Grand Slam matches played in tennis history. On his journey to the third round of the Australian Open, Djokovic surpassed Roger Federer’s previous record with 430 matches played.