World No. 2 Novak Djokovic, who had a disappointing performance last week at the ATP Finals, helped Serbia get off to an unbeaten start against Japan at the ongoing Davis Cup Finals. On Wednesday, Djokovic beat Yoshihito Nishioka 6-1, 6-2 to clinch the win after Filip Krajinovic beat Yuichi Sugita 6-2, 6-4. he Serbian wrapped up the contest in just one hour and seven minutes.