Novak Djokovic beats John Isner in eight -set marathon as Spain beat USA in the Davis Cup tie . In other ties , defending champions Spain shrugged off the absence of the injured Rafael Nadal to beat Switzerland 4-1 to set-up a quarterfinal clash with France . Serbia reach quarterfinals of the World Group for the third time . Defending champions Spain will play France in pick of the last five ties .
Novak Djokovic beats John Isner in eight -set marathon as Spain beat USA in the Davis Cup tie . Serbia reach quarterfinals of the World Group for the third time . Defending champions Spain will play France in pick of the last five ties .