Novak Djokovic wins opening match in Marin Cilic . Beats U.S. Open champion Marin Cilic three -1 6-1 . The two-time defending champion at the ATP World Tour Finals might have been expected to be tested by the new U.S. Open champion Marin Cilic , in their Group A opener , but it turned in to a one-sided rout Monday . Stanislas Wawrinka thrashes Tomas Berdcyh by same margin . 11th day wins for Roger Federer and Roger Federer .
Novak Djokovic wins opening match in Marin Cilic . Beats U.S. Open champion Marin Cilic three -1 6-1 . Stanislas Wawrinka thrashes Tomas Berdcyh by same margin . 11th day wins for Roger Federer and Roger Federer .