Juan Martin del Potro came back from two sets down and saved two match points to beat sixth seed Dominic Thiem in a raucous US Open classic.
The 24th seed, cheered on by a large Argentine contingent on the Grandstand court, won 1-6 2-6 6-1 7-6 (7-1) 6-4.
Despite feeling ill and requiring treatment, he came through in three hours and 35 minutes to set up a quarter-final against Roger Federer.
The Swiss third seed beat Germany’s Philipp Kohlschreiber 6-4 6-2 7-5
Roger Federer has admitted that he is looking forward to a US Open reunion with Juan Martin del Potro, despite predicting that the match will be “different” to their 2009 final.
Federer and Del Potro played out a Flushing Meadows classic as Del Potro powered his way to his one and only Grand Slam title, and both players have endured twists and turns in their career since that showdown in New York.
The pair have had to fight hard in order to reach the last eight of this year’s tournament, and Federer says that he does not expect the contest to be played in a similar fashion to that of eight years ago.
The 36-year-old told reporters: “It’s a good match to look forward to. Reminds me clearly of the 2009 finals that we had, which was an epic, too. I hope we can produce another good one.
“I think we’re different players today. We both play different. Because of his surgery, I think his backhand has changed. He uses his slice much more. Just alone because of that, the game would be different.
“I’m playing more aggressive, as well, on the return. I play shorter points. I don’t use my slice as much, whereas he does now. It’s a bit of a change, you know.”
The winner of the match will face either Rafael Nadal or Andrey Rublev for a place in the final.