Djokovic eases past Nishikori at ATP World Tour Finals

World No. 1 Novak Djokovic breezed past Japan's Kei Nishikori in the opening match of the ATP World Tour Finals here on Sunday.

Djokovic, bidding for a record fourth straight end-of-season title, beat the world 8th ranked Japanese 6-1, 6-1.

It was the Serb's 15th consecutive win at the O2 Arena.

Roger Federer, now ranked third, plays Tomas Berdych of Czech Republic later in the evening. Endi