New York - Andy Murray crashed out of the US Open in the fourth round on Monday, his earliest Grand Slam exit in five years, while 17-time major winner Roger Federer advanced to the quarter-finals.
South African 15th seed Kevin Anderson stunned British third seed Murray 7-6 (7/5), 6-3, 6-7 (2/7), 7-6 (7/0) to end his run of 18 consecutive major quarter-finals since the 2010 US Open.
"That's 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.
"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 reached his first Grand Slam quarter-final after seven prior fourth-round defeats.
"It was the match of my life," Anderson said. "This is a great accomplishment for me."
Anderson, who won his third career title two weeks ago at Winston-Salem, is the first South African in New York's last-eight since Wayne Ferreira in 1992.
"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."
Anderson, 1-5 in prior matches against Murray, fired 25 aces in ending an 0-15 career hoodoo against top-10 opponents to book a last-eight date with Swiss fifth seed Stan Wawrinka.
Reigning French Open champion Wawrinka defeated US left-hander Donald Young 6-4, 1-6, 6-3, 6-4.
The Swiss 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.
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.
Murray, the 2012 champion, 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.
Swiss second seed Federer, seeking his sixth US Open title, dispatched US 13th seed John Isner 7-6 (7/0), 7-6 (8/6), 7-5 to reach a quarter-final against French 12th seed Richard Gasquet, who ousted Czech sixth seed Tomas Berdych 2-6, 6-3, 6-4, 6-1.
"Of course Roger will be the favourite of the match but I will have nothing to lose," said Gasquet, who is 2-14 lifetime against the Swiss star.
Federer, trying to become at 34 the oldest US Open champion since Ken Rosewall in 1970, stretched his US Open win streak over Americans to 12 since losing to Andre Agassi in 2001.
Isner had held in 110 consecutive US Open service games since broken by Germany's Philipp Kohlschreiber in the third round in 2013, but Federer ended that streak on match point to close out the victory in two hours and 39 minutes.
"John has one of the best serves in the game," Federer said. "You have just got to hang around and win your service games."
Federer also inflicted the first shutout tie-break loss upon Isner.
"I served very well, picked up his second serves," Federer said. "You've got to get a little lucky."
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."
In a match-up of 29-year-old past US Open semi-finalists, Gasquet overcame a poor start to reach his second US Open quarter-final. He reached the 2013 US Open semi-finals.
"I started really bad. I was not confident on the court," Gasquet said. "The second set was better. I played more aggressive. The fourth set was incredible. It's a great victory for me to be in the quarter-finals."
US Open results on Monday, the eighth day of the 2015 tournament at Flushing Meadows (x denotes seeded player):
Stan Wawrinka (SUI x5) bt Donald Young (USA) 6-4, 1-6, 6-3, 6-4
Kevin Anderson (RSA x15) bt Andy Murray (GBR x3) 7-6 (7/5), 6-3, 6-7 (2/7), 7-6 (7/0)
Richard Gasquet (FRA x12) bt Tomas Berdych (CZE x6) 2-6, 6-3, 6-4, 6-1
Roger Federer (SUI x2) bt John Isner (USA x13) 7-6 (7/0), 7-6 (8/6), 7-5
Petra Kvitova (CZE x5) bt Johanna Konta (GBR) 7-5, 6-3
Flavia Pennetta (ITA x26) bt Samantha Stosur (AUS x22) 6-4, 6-4
Victoria Azarenka (BLR x20) bt Varvara Lepchenko (USA) 6-3, 6-4
Simona Halep (ROM x2) bt Sabine Lisicki (GER x24) 6-7 (6/8), 7-5, 6-2
Martina Hingis/Leander Paes (SUI/IND x4) bt Simona Halep/Horia Tecau (ROM) - walkover
Yung-Jan Chan/Rohan Bopanna (TPE/IND x2) bt Su-Wei Hsieh/Henri Kontinen (TPE/FIN) 7-6 (9/7), 5-7, 13-11