LONDON – American Jack Sock booked a spot in the last four of the ATP Finals with a 6-4, 1-6, 6-4 win on Thursday night over Germany’s Alexander Zverev.
Sock had the final answer in a sloppy round-robin match at the O2 Arena in London in which the players combined for 12 double faults and repeatedly squandered leads.
The 25-year-old American staved off six break points to claim a tight first set before going off the boil to lose the second and fall behind an early break in the third.
But Zverev’s serve deserted him in the final stretch of the match, when he committed five of his eight double faults and lost serve three times.
Zverev fell behind 4-1 in the third set before fighting back to draw level at 4-4, but he dropped serve one last time in the 10th game to bow out of this elite, year-end tennis event.
“That was a roller coaster match for sure,” Sock said after his second win in three matches in Group Boris Becker.
The 20-year-old German, meanwhile, blamed nerves for his defeat.
“I choked. It’s quite easy. Won the second set 6-1. I was 1-0 with a break. He got a point penalty. I was down 1-4 within 10 minutes where I didn’t put many balls in the court,” the third-ranked Zverev said. “So, yeah, I just choked.”
Earlier Thursday, Swiss world No. 2 and Group Boris Becker winner Roger Federer remained unbeaten at this indoor hard-court event thanks to a come-from-behind 6-7 (5), 6-4, 6-1 victory over Croatia’s Marin Cilic.
In Saturday’s semifinals, Sock will square off against Group Pete Sampras winner Grigor Dimitrov of Bulgaria, while six-time champion Federer will play the winner of Friday’s match between Austria’s Dominic Thiem and Belgium’s David Goffin.