New York: Novak Djokovic, dogged by nagging questions about his stamina and guts when pressed in big matches and high temperatures, showed fortitude against an old friend at the U.S. Open on Tuesday.
The 23-year-old Serb dug deep to come back after trailing two sets to one and down a break in the fourth set to overtake his Davis Cup team mate Viktor Troicki 6-3 3-6 2-6 7-5 6-3 in the first round on Arthur Ashe centre court.