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 in New York.
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.
The Russian, now ranked 53rd after peaking at 49th last month, had beaten seventh seed Grigor Dimitrov in the second round.
He saw off Goffin in two hours and five minutes, with the Belgian hampered by a knee injury.
“I’m a little bit lucky to be in the quarter-final but of course I’m enjoying it, and I will try to do my best in the next match,” said Rublev.
“Rafa is the real champion and I’m just going to try to enjoy it – this is the quarter-final and I have nothing to lose.”
‘This sport is about victory’
Nadal has practised with Rublev in Majorca, describing him as a “great guy”, but he did not accept that the teenager would be free of pressure when they meet.
“Of course he’s young, but at the same time, he’s in the quarter-finals,” said Nadal.
“He has a chance to be in the semi-finals for the first time of his career, and I have been there a couple of times.
“So of course he has things to lose. And of course I have things to lose and things to win.
“But I tell you one thing, this sport is about victory. This is not about defeats. At the end of your career, nobody remember your defeats, your losses. People remember the victories.
“For everybody it’s everything to win, you know. And that’s it.”
‘Of course, it’s better to be 19 than 31’
Dolgopolov, ranked 64th, had won two of his previous three matches against Nadal, but rarely threatened in New York.
The Spaniard fired 11 forehand winners off his dominant side, while Dolgopolov made 39 errors as his game grew increasingly wayward.
A double-fault and a forehand error gave up the first break of serve in game three, and Nadal came through the only testing moment by saving two break points in game six.
A brilliant backhand cross-court winner gave the Spaniard a double break, and soon after the set, before Dolgopolov’s hopes effectively ended midway though the second set.
Two errors gave up the crucial break at 4-4 and Nadal rolled through nine of the last 10 games to complete a comfortable afternoon’s work.
Looking ahead to the quarter-final, and an opponent who was four years old when the Spaniard turned professional, Nadal said: “Of course, it’s better to be 19 than 31.
“I always wanted to be young. Even when I was eight years old, I was not very happy when it was my birthday to be nine. Still the same – I am 31, and I am not happy when my birthday going to be 32.
“I am happy being young, no? I don’t want to get older.”