On Tennis: Big Three Is Down to Djokovic, Raising Questions Atop Men’s Tennis

On Tennis: Big Three Is Down to Djokovic, Raising Questions Atop Men’s Tennis: Is a final four of Novak Djokovic, Andy Murray, Tomas Berdych and David Ferrer indicative of the A.T.P.’s depth, or a sign that the Big Three’s stranglehold has weakened?