Novak ##ović defeated John Isner in five - set marathon as Serbia beat USA in Davis Cup tie . A single break in the first game gave Djokovic a crucial advantage , but his American opponent proceeded to save six match points before finally netting a forehand , the home hero sinking to his knees after an exhausting ordeal . Serbia reach quarterfinals of the World Group for the first time . defending champions Spain will play France in pick of the last eight ties .
Novak ##ović defeated John Isner in five - set marathon as Serbia beat USA in Davis Cup tie . Serbia reach quarterfinals of the World Group for the first time . defending champions Spain will play France in pick of the last eight ties .