Speaking with Eurosport, the 2009 ATP Finals winner Nikolay Davydenko was asked who among Roger Federer, Rafael Nadal and Novak Djokovic will retire first. Davydenko said: "Federer. He will be 39 years old next year and I think he wants to play the Olympic Games for the last time.
I do not know if he wants to reach 40 years and beat some records... It will depend on his results. If it's easy for him to reach quarter-finals, semis, finals, he will stay in the top ten rankings which is good. Not the number one, but the top 5, 7, 10.
If 40-year-old beats the top ten players, including many of them (who are) 23 years old, then it means the younger generation is just better." Davydenko also revealed a conversation he had with Federer earlier this year: "In Shanghai, I spoke to him and he said he doesn't recover as early as before, it doesn't take one day but three or four days.
I think his body no longer bothers him, it's about his mind. If he stays focused, then he will still be at the top. Roger always remembers me that I beat him in Doha. And then the Australian Open match. I asked him, Why did you go to the bathroom after the first set when I was leading? And he said I did not go to the bathroom.
The sun was bothering me and I waited for it to be set. I am like, You are saying a false thing, just say that I am the best. Each one had his moments and injuries, but he quickly recovered. He can still play for a while."