Novak Djokovic wins opening match in ATP World Tour Finals . `` It was a great performance obviously , '' he said after his quickfire victory . Beats Australian Open champion Marin Cilic 6 - 1 6 - 1 . Stanislas David thrashes Tomas ##si by same margin . First match wins for Roger Federer and Kei Nishikori .
Novak Djokovic wins opening match in ATP World Tour Finals . Beats Australian Open champion Marin Cilic 6 - 1 6 - 1 . Stanislas David thrashes Tomas ##si by same margin . First match wins for Roger Federer and Kei Nishikori .