Former Top 10 and US Open champion chooses greatest player between Djokovic and Federer

Novak Djokovic and Roger Federer, alongside Rafael Nadal, are two of the names that come up the most when talking about tennis' greatest player ever.

• Former World No. 1 reveals the greatest tennis players in history, excluding one from the ‘Big Three’
• He was a Grand Slam champion, lost to Borg in one of the greatest matches ever, and tragically died at age of 40