World number two Novak Djokovic had to come back from set down to beat Dominic Thiem from Austria 6-7 6-0 6-2 in his opening match at the ATP World Finals in London. In the same group this evening Milos Raonic broke serve once in each set to win against Frenchman Gael Monfils 6-3 6-4. The big serving Raonic will face Djokovic next on Tuesday.