Juan Martin del Potro revealed a few months ago that he "could not accept" a life without tennis. This is probably one of the reasons why the Argentinian has not yet given up hope of a comeback. And that, although the "Tower of Tandil" still hasn't got his serious knee problems under control, despite several options.

"The physical issues and my knee are something I work on every day," del Potro revealed in an interview with journalist Danny Miche. He has not forgotten how to play tennis: "It will never be a problem to pick up a racket and see how I feel."

Del Potro played his last match on the tour over a year ago at his home tournament in Buenos Aires. With tears and great pain, the former world number three said goodbye to his fans. Many observers assumed a final farewell, but the 34-year-old doesn't want to know anything about it for the time being.

"I'll leave the time window open. At least until the US Open," said del Potro, who surprisingly won the Grand Slam tournament in New York in 2009. "I still have time. I'll start training and see how my leg reacts." Then he could judge "whether I can do it or not".