LONDON – Jack Sock maintained his hopes of qualifying for the semifinals of the ATP World Tour Finals by beating Marin Cilic 5-7, 6-2, 7-6 (4) on Tuesday.
World No. 9 Sock, who was the last player to qualify for the season-ending championship after winning the Paris Masters title, needed two hours and 28 minutes to defeat the fourth-seeded Croatian at London’s 02 Arena.
The American kept his nerves in check and played with great maturity in the tiebreaker of the last set to win the match.
If second-seed Roger Federer defeats Alexander Zverev later Tuesday in two or three sets, the Swiss great will advance to the semifinals. In that scenario, Sock would play against Germany’s Zverev to reach the penultimate round.