Alexander Zverev took another big step towards a second Grand Slam title by beating Dutchman Botic van de Zandschulp 6-2 7-5 6-1 to reach the U.S. Open semi-finals, where the German will take on Karen Khachanov.

Zverev looked far from convincing on serve at Arthur Ashe Stadium and coughed up five double faults in an erratic start, but van de Zandschulp leaked forehand errors to allow the top seed to break in the fifth game and then take the first set.

Van de Zandschulp regrouped in the second set and came close to levelling the contest, but Zverev absorbed the pressure and reeled off three games in a row towards the end as the momentum swung firmly in the German's favour.

Zverev, the 2020 runner-up, fired an overhead smash to break early in the third set and cruised home from there to reach his third semi-final in New York.