Pat Cash believes Roger Federer, Rafael Nadal, and Novak Djokovic are 'not normal people,' because of their mentalities.
The trio have overseen an unprecedented era of collective dominance in men's tennis, with them massing an incredible 57 Grand Slam titles between them.
Cash says he believes Djokovic to be the best of the three, although he says they are all remarkably special.
“They are monsters," Cash said of Roger Federer, Rafael Nadal, and Novak Djokovic.
"They are not normal people, human beings. No one can do what they are doing.
"It takes a different mentality than normal people. Andy Murray has one too.
"To be the best you need some kind of obsession and they have it, beyond the fact that they are exceptional athletes.
"Federer could have excelled in any generation, no matter what racquet.
"Rafa and Novak have created something new, especially Rafa.
"The way he plays on clay is absolutely phenomenal [but] I don't see Rafa being able to beat Roger on grass.
"Novak can do it on all surfaces."
Currently, Roger Federer and Rafael Nadal have 20 Grand Slam titles a piece, while Novak Djokovic is just three behind with 17.
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