Former US Open champion Juan Martin del Potro came back from a two-set deficit to win an epic five-set thriller against Dominic Thiem.
Del Potro battled with poor eyesight and even contemplated retiring the match, before pulling off his first two-set deficit comeback in a major to win 1-6 2-6 6-1 7-6 (7-1) 6-4 at the 8,000-seater Grandstand court.
“I played one of the epic matches of my career here at the US Open, which is my favourite tournament, in front of a great crowd,” the Argentine said.
“I was thinking to retire in the middle of the second set because I couldn’t breathe, I couldn’t move well, and Dominic was dominating the match so easy.”
The Argentine’s remarkable comeback earns him a quarter final match-up with Roger Federer, the man he beat for his only Grand Slam title – the 2009 US Open.
Federer made light work of Philipp Kohlschreiber in front of 24,000 spectators at Arthur Ashe Stadium, beating the German 6-4 6-2 7-5. Despite taking a medical time out at the end of the second set to attend to a back problem, Federer took why was relatively an easy victory without facing a single break point.
Elsewhere, Rafael Nadal was in emphatic form, dispatching Ukraine’s Alexandr Dolgopolov 6-2 6-4 6-1 in just one hour and 41 minutes.
The world number one will play 19-year-old Andrey Rublev in the last eight. Rublev beat Belgian ninth seed David Goffin 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.
Rafael Nadal and Roger Federer will play each other for the first time at the US Open if they both win their quarter final matches.
Karolina Pliskova beat Jennifer Brady 6-1, 6-0
Coco Vandeweghe beat Lucie Safarova 6-4, 7-6
Kaia Kanepi beat Daria Kasatkina 6-4, 6-4
Madison Keys beat Elina Svitolina 7-6, 1-6, 6-4