Juan Martin del Potro buoyed by boyhood friends in quest for second US Open title
Djokovic has won 14 of their 18 career meetings, including in the quarter-finals of the 2012 US Open.
Djokovic has won 14 of their 18 career meetings, including in the quarter-finals of the 2012 US Open.
After the Argentine blasted a forehand winner to close out the second set, Nadal could not continue.
