Djokovic: Nadal can be the greatest

Novak Djokovic has backed Rafael Nadal to become the greatest player of all time after failing to prevent the Spaniard from completing a sweep of the four grand slam titles in New York.

Nadal claimed the US Open with a 6-4 5-7 6-4 6-2 success at Flushing Meadows to add to the crowns won previously at the Australian Open, French Open and Wimbledon.