Jack Sock booked a place in the semifinals of the ATP Finals with a surprise 6-4, 1-6, 6-4 win over German Alexander Zverev.
A bruising first set went in Sock’s favour before Zverev took the second with ease. When Zverev maintained his assault with a break in the first game of the deciding set, Sock smashed the ball into the crowd and was punished with a penalty point.
Sock channelled that rage with a burst of power hitting as he won four successive games. In a dramatic finish, Zverev roared back from 4-1 down to draw level, only for Sock to pounce on his first match point.
David Goffin survived a shaky start against good friend Dominic Thiem on Friday to win 6-4, 6-1 and advance to the semifinals.
The result: Boris Becker Group : Jack Sock bt Alexander Zverev 6-4, 1-6, 6-4 .
Pete Sampras group: David Goffin bt Dominic Thiem 6-4, 6-1.
