DECKED out in a garish purple T-shirt, Rafael Nadal began his ATP World Tour Finals campaign with a hard-fought win over Andy Roddick. The American took advantage of Nadal’s shaky service to claim the opening set 6-3. But Nadal rallied to claim the second on a tie break and the third 6-4 to complete his first ever win at London’s O2 Arena. In yesterday’s other Group B match, Novak Djokovic beat Tomas Berdych 6-3 6-3.