Second seed Daniil Medvedev ended qualifier Botic van de Zandschulp's battling run to reach the US Open semi-finals and keep his bid for a maiden Grand Slam trophy alive.
The Russian raced through to a two-set lead but Van de Zandschulp, despite looking exhausted, hit back.
The Dutchman, 25, saved a match point in the fourth set but could not prevent Medvedev from winning 6-3 6-0 4-6 7-5.
Medvedev will face either Felix Auger-Aliassime or Carlos Alcaraz next.
Medvedev is seen as the most likely challenger to Novak Djokovic's hunt for a calendar Grand Slam.