LONDON – 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 in a firecracker of a match on Thursday.
The world number nine, who barged through the back door to qualify for the London showpiece by winning the Paris Masters, triumphed 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.
Six-times champion 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.
Talk of a possible Federer-Zverev re-match in Sunday’s final, after their high-quality duel on Tuesday, was doing the rounds but Sock, nicknamed ‘Showtime’, was not listening.
The 25-year-old from Kansas looked to have blown himself out when a 4-1 lead evaporated in the decider, but the 20-year-old Zverev admitted later he “choked” when serving at 4-5, double-faulting and then bunting a forehand wide to hand Sock victory.
“That was a rollercoaster of a match for sure, that’s been the theme of my last few weeks, hang in there and keep fighting,” Sock, who seemed to be imploding when he received a penalty point at the start of the third set, said on court.
