Karen Khachanov is through to the Paris Masters semifinals after he defeated Alexander Zverev 6-1 6-2.

Zverev’s serve was broken four times in a row on Friday to give Khachanov the first set as the German world No.5 struggled with a shoulder injury.

The 21-year-old, clearly below par as 36 unforced errors and seven double-faults, tried to fight back in the second set but the errors piled up to confirm Khachanov as the winner after 70 minutes.

Khachanov advances to face either defending champion Jack Sock or Austria’s Dominic Thiem in Saturday’s final four.