In my younger days I played Tennis and followed the game very closely. Rod Laver, Stan Smith, Chris Everet, etc were the stars. But what he's accomplished is truly legendary. I thought nobody would exceed Pete Sampras, but then Federer, Serena Williams and Nadal came along, now he's gone above all those as well.
I played tennis also, in high school and one year at ND. Used to go to the US Amateur every year at Forrest Hills. Of course they eventually let pros play and they moved to Flushing Meadows.