Andy Murray crashed out in the fourth round of the US Open, making his earliest Grand Slam exit since 2010 to end his run of 18 consecutive major quarter-finals.
South African 15th seed Kevin Anderson stunned the British third seed 7-6 (7/5), 6-3, 6-7 (2/7), 7-6 (7/0) to reach his first Grand Slam quarter-final after seven prior fourth-round defeats.
"It was the match of my life," Anderson said on Monday. "This is a great accomplishment for me."
Not since a third-round exit in the 2010 US Open had Murray been eliminated so early at a Grand Slam tournament.
"That's obviously something that is disappointing to lose because of that. That's many years' work that's gone into building that sort of consistency. To lose that is tough," said Murray, the 2012 champion.
"Also to lose a match like that, that was over four hours, tough after a couple of tough matches earlier in the tournament as well, it's a hard one to lose, for sure."
Anderson, 1-5 in prior matches against Murray, fired 25 aces in ending an 0-15 career hoodoo against top-10 opponents and his fourth-round hex to book a last-eight date with Swiss fifth seed Stan Wawrinka, the reigning French Open champion.
"I'm just so excited to be through," said Anderson. "Beating a guy like Andy, I really feel like I've taken a step forward. It's amazing. I feel like it's a great accomplishment."
Wawrinka defeated US left-hander Donald Young 6-4, 1-6, 6-3, 6-4, at Arthur Ashe Stadium.
He dropped his first set of the tournament but reached an eighth quarter-final in his past nine Grand Slams, denying 68th-ranked Young his first Slam quarter-final.
Anderson is the first South African in New York's last 16 since Wayne Ferreira in 2002.
He came in off a third career title at Winston-Salem.
With New York City FC and former England midfielder Frank Lampard watching from the player's box, Murray fell behind two sets and a break, roared back, but ultimately could not win the tension-packed encounter at Louis Armstrong Stadium.
"That court is a lot quicker than Ashe," Murray said. "I felt like I was on the back foot quite a lot. Wasn't able to play that offensively."
Murray had 49 winners and 20 unforced errors, but did not make a forehand winner until the last game of the second set. Anderson blasted 81 winners to 57 unforced errors.
Anderson ripped a forehand winner on the final point of the opening tie-break to take the set after 69 minutes, then broke Murray's first service game of the second set on the way to a 5-1 edge.
Murray broke back and held and had a break chance in the ninth game, but Anderson saved it and finally took the set on his fifth chance, ripping his 12th ace of the match up the middle.
Murray unleashed a profanity-laced tirade to himself picked up by courtside microphones, unhappy the time Anderson took for a toilet break.
He promptly surrendered a break to open the fourth, sending Murray to his chair ranting.
"You get these grey areas all the time," Murray said between sips from his water bottle. "They just exploit them and you do nothing."
Murray dominated the third set tie-breaker and denied Anderson on two break points in the fourth game of the fourth set on the way to the last tie-breaker, in which Anderson never blinked.
Young, the first player since Gilles Muller in 2008 to rally twice from two sets down in a US Open, 0-17 in such situations before this week, but he fell to 3-18 against top-10 opponents.
Wawrinka, 30, was upset by Young in a fifth-set tie-breaker at the 2011 US Open, but took the first set on a backhand return winner in the third game.
Young, 26, won the second set as the Swiss struggled with the forehand, Wawrinka smashing his racquet to the cement at one stage in frustration.
"Sometimes you don't control yourself. You need to put the pressure out," Wawrinka said. "I played really well after."
"The set was so quick. I wasn't there mentally. Calmed down a little bit. I began to be more aggressive, started moving my feet better."
Wawrinka raced ahead 5-0 in the third set and hung on to finally take the set on a running backhand winner, then opened the fourth set with a break and held to the end.
Swiss second seed Roger Federer, winner of a record 17 Grand Slam titles, was set to face US 13th seed John Isner in the last match at Arthur Ashe Stadium.
The winner advances to a quarter-final against either Czech sixth seed Tomas Berdych or French 12th seed Richard Gasquet, both past US Open semi-finalists.
