World No. 1 Novak Djokovic defeated American John Isner 7-6 (5) 6-2, 7-5 to give Serbia a 1-0 lead in a Davis Cup quarterfinal on Friday.
Isner was ahead by a service break in the initial stages of the first set, but couldn't hold on to the advantage. He had won his five previous tiebreakers in Davis Cup action, but couldn't keep that streak going against Djokovic.
In the second set, Djokovic secured service breaks in the third and seventh games. And in the final set, Djokovic broke Isner's serve in the 11th game. Djokovic won the final 12 points of the match.
Sam Querrey will try to put the United States on the scoreboard when he takes on Viktor Troicki in the second match of the afternoon.