They will now play Croatia at home on July 9-11 in the quarterfinals of the premier team event in tennis after their first-ever victory in the World Group . Novak Djokovic beats John Isner in five-set marathon as Serbia beat USA in Davis Cup tie . The Serbian player won 6-3, 7-6 (2), 6-4 to claim his first title since the 2012 London Olympics and become world number one. Defending champions Spain will play France in pick of the last eight ties .
Novak Djokovic beats John Isner in five-set marathon as Serbia beat USA in Davis Cup tie . The Serbian player won 6-3, 7-6 (2), 6-4 to claim his first title since the 2012 London Olympics and become world number one. Defending champions Spain will play France in pick of the last eight ties .