
Novak Djokovic of Serbia and his younger brother and teammate Djordje Djokovic (front) play against Jack Sock of the United States and Vasek Pospisil of Canada during the men's doubles quarterfinal at the China Open tennis tournament in Beijing, China, Oct. 8, 2015. Novak Djokovic and Djordje Djokovic lost the match 0-2. (Xinhua/Xing Guangli)















