'Roger Federer's serve was not the most powerful but...', says former star

"To my tennis family and beyond. Of all the gifts that tennis has given me over the years, the greatest is undoubtedly meeting the people along the way: my friends, my rivals and especially the fans. I want to share some news with you. As everyone knows, the last three years have been challenging for me in the form of injuries. I tried hard to get back, but my body sent me clear messages. Tennis has treated me better than I ever dreamed of, but I have to admit that the time has come to end my pr