Roger Federer, Jack Sock secure ATP FInals semis berth

Jack Sock became the first American to reach the last four of the ATP Finals for 10 years when he stunned world number three Alexander Zverev 6-4, 1-6, 6-4 to prolong his London adventure. Roger Federer had already won the Boris Becker group, having battled back to beat Marin Cilic earlier to post a perfect round-robin record at the event for a 10th time. Federer won 6-7(5), 6-4, 6-1 leaving the stage set for Zverev and Sock to slug it out for the runners-up spot and a semi-final against Bulgarian Grigor Dimitrov. (Video Courtesy: SNTV)