Roger Federer who had already topped the Boris Becker group at the ATP Finals in London, marched on to the semi – finals with an unbeaten record with a victory against Marin Cilic this afternoon 6-7 6-4 6-1. This evening American Jack Sock beat third seed Alexander Zverev 6-4 1-6 6-4 to finish second in the group and set up a semi-final match against Grigor Dimitrov on Saturday.