Jack Sock Upsets Zverev @ ATP Finals

American Jack Sock is having a great end of the year. After winning Paris Master last week, he is also showing some high-level tennis at the Nitto ATP Finals. By beating Zverev he placed second in Boris Becker group and he is off to the semi-finals. There is one more spot for grabs in the semi-finals, where Thiem and Goffin will battle it out tomorrow 2 pm local time. Stayed tuned!