23 according to the official website of the ATP Chinese news, London local time Sunday night, the last game of the 2015 season, the ATP world tour at the O2 Arena wonderful ending. Third defending champion Novak Djokovic and sixth tournament champion Federer to 2015 the Barclays ATP World Tour Finals men's singles title launched fierce competition, and ultimately by the Serbs to 6-3, 6-4 win, for the fourth consecutive year harvest finals...