For Federer though, he cannot believe that he has got so long in his career while still being competitive and that he began a routine which has allowed him to go on so long.
He said that from his perspective, he was inspired by the likes of Ken Rosewall and Jimmy Connors who went towards their 40's to continue and find the right routine.
"I am not 40 years old yet, but I am not far away.
Being competitive at 38 seems unreal. My dream and hope of playing for many years after becoming world No. 1 in 2004 was there. I spoke with my fitness coach Pierre Paganini, my fitness trainer, who is still working with me and I told him, I would love to be able to play against different generations.
We will have a routine that allows me to achieve it. We will start scheduling it and here we are, 15 years after; I am still at the top with the best guys and it makes me very happy. It was a goal. But Honestly if you asked me at the time, I didn't think I would play at 34, 35 years.
Not many guys achieved it. You ask yourself how it came, because the guys who achieved it was not at this level or they did it 40 years ago like Ken Rosewall or Jimmy Connors."