What Novak Djokovic must do to defend world No 1 crown from Rafael Nadal, Roger Federer

Novak Djokovic is in a precarious position as the world No 1 - but how can he avoid being dethroned by Rafael Nadal or Roger Federer.

from Daily Express :: Tennis Feed https://www.express.co.uk/sport/tennis/1182569/Novak-Djokovic-world-No-1-Rafael-Nadal-Roger-Federer
via Express