German fifth seed Alexander Zverev fought back from a set down to reach his first US Open semi-final by beating a battling Borna Coric.
Zverev, 23, crumbled in the first set as the Croatian 27th seed threatened his hopes of a first Grand Slam title.
But two impressive tie-breaks and a late break in the fourth set gave the German a 1-6 7-6 (7-5) 7-6 (7-1) 6-3 victory.
Zverev will play Pablo Carreno Busta or Denis Shapovalov next.
Spanish 20th seed Carreno Busta and Canadian 12th seed Shapovalov play later on Tuesday.
More to follow.