Russian teenager Andrey Rublev knocked out Belgian ninth seed David Goffin to set up a US Open quarter-final with Rafael Nadal.
Rublev, 19, won 7-5 7-6 (7-5) 6-3 to become the youngest man to reach the last eight at Flushing Meadows since Andy Roddick in 2001.
Nadal, 31, saw off Ukraine's Alexandr Dolgopolov 6-2 6-4 6-1 in just one hour and 41 minutes.
The Spaniard returns to the last eight for the first time in four years.
He will face one of the sport's rising stars in Rublev, who only broke into the top 100 in June and the top 50 in July.