In a rare interview, Rafael Nadal’s Coach and uncle, Tony Nadal was asked the following question:

“Recently, we read that you were saying [a quote from Pablo Picasso]: ‘When inspiration comes, let it find me working’…”
To which he answered: “This is an essential fact of life. I do not think people who succeed or stand out are only the fruit of labor. I do not think Roger Federer, Michael Jordan are just the result of work… The question is that if you do not work, you would not be one of them. And, as far as most people are concerned, I am indeed convinced that the work helps us totally. I am a defender of work, especially the mental effort.” [Source]