qqp question1: How do you think Federer, Nadal, Djokovic, Murray, Wawrinka, Delpo & Cilic rank in terms of potential when it comes to greatest spot in the tennis? question2: How would you rank Federer, Nadal, Djokovic, Murray, Wawrinka, Delpo and Cilic in terms of greatness achieved and potential spot in the history of sport?