Defending champion Andy Murray was hampered by a hip injury as he was knocked out of Wimbledon in the quarter-finals by Sam Querrey.
Querrey, 29, won 3-6 6-4 6-7 (4-7) 6-1 6-1 to become the first American man to reach a Grand Slam semi-final since Andy Roddick at Wimbledon in 2009.
Murray, 30, led by a set and a break but the Briton lost 12 of the last 14 games as he struggled physically.
An injury to Novak Djokovic means Murray will remain as world number one.
Second seed Djokovic needed to win the title to return to the top of the rankings, but an elbow injury caused him to pull out in the second set of his quarter-final against Tomas Berdych.
Murray looked on course for an eighth win in nine matches against Querrey when he led by a set and a break, but less than two hours later he was out, after the American fired down his 27th ace.
Querrey took his chance superbly, hitting 70 winners, 30 of them from the net as he attacked at every opportunity.
For Murray, the hip injury that disrupted his build-up to Wimbledon had finally caught up with him.
“My hip’s been sore most of the event and it was just a little bit too sore today,” he later told BBC Sport.
“At the end I was obviously struggling a bit on serve, and when you’re playing a guy who serves huge himself, and you’re not getting many free points on your own serve, it’s very difficult because you’re not dictating many of the rallies.
“You’re then having to do more and more moving, and that was tough at the end.”
After breaking serve to lead 4-3 in the second set, letting out a loud “come on!”, Murray dropped serve twice in a row, his opponent firing a brilliant backhand to clinch the set.
Any thought that it was a momentary lapse from the champion disappeared when Murray was broken again serving for the third set, but he took the tie-break on his fourth set point and seemingly regained control.
In fact, it was Querrey who took command as Murray appeared underpowered and unable to move freely.
The Scot won just nine points on serve in each of the fourth and fifth sets, with an average serve speed down at just 108mph, allowing Querrey to tee off on the return.
The American played a magnificent point at the net to break for the eighth time, serving out the match after two hours and 41 minutes.
Querrey will now face seventh seed Marin Cilic in the semi-final after the Croat beat Gilles Muller in five sets.
Muller – who beat Rafael Nadal in just under five hours on Monday – took the first set but former US Open champion Cilic came through to win 3-6 7-6 (8-6) 7-5 5-7 6-1.
‘I gave everything I had’
Murray was struggling with a hip injury in the build-up to Wimbledon, pulling out of two exhibition matches and missing three days of practice before his opening match.
But he would not tell the post-match news conference exactly what his injury was, only that he regretted a missed opportunity to add to his two Wimbledon titles.
He said: “I tried my best, right to the end I gave everything I had, and I’m proud about that but it’s obviously disappointing to lose.
“There was an opportunity there so I’m sad that it’s over.
“Before the tournament it was very short-term solutions because you want to play Wimbledon.
“We were looking at short-term solutions and managed to get through a bunch of matches and did OK.
“Now I’ll sit down with my team and look at the longer term, and come up with a plan for what I have to do next.”
Querrey, the 24th seed, reached his first semi-final at his 42nd Grand Slam – a new record.
He said: “I didn’t start my best but I kept with it, kept swinging away, then really found a groove in the fourth and fifth sets and then everything started falling my way.
“It feels great – this is a dream come true, to be in the semi-finals and to have it at Wimbledon makes it feel more special.”
Analysis – ‘It was evident his hip had deteriorated’
Former British number one Tim Henman
You have to give Querrey credit for the level of tennis he played but obviously there’s a big question mark over what has been Murray’s fitness over the past three or four weeks.
His hip is one of those things where you are hoping that, if you have got a niggle, it gets better as the tournament goes on but to see him in so much discomfort it was pretty evident that it’s deteriorated, and movement is such an important part of Murray’s game.
Any lack of movement is a hindrance physically but I think it’s also a distraction mentally.
Murray was up a set and a break at 4-3 in the second set and you think perhaps he can take advantage of this and get two sets up, but you could see with lots of different movements he was certainly hobbling.
When he was trying to change direction, pushing off the compression in the the hip joint was uncomfortable. At this level and stage of the tournament you know you have got to be 100% fit or, if not, very close to it.
That was not the case with Andy, and it is very disappointing for him.
‘A couple of days after Paris it felt pretty sore’
The first anyone outside Team Murray knew of a hip issue was when he pulled out of an exhibition match at the Hurlingham Club on 27 June, six days before the start of Wimbledon.
Murray would then miss three days of practice, withdrawing from a second planned match at Hurlingham on 30 June, before taking to the All England Club practice courts.
He was clearly limping between practice points and that continued into his matches once the championships began.
Murray revealed that he was taking two ice baths a day and doing 20 minutes’ worth of extra exercises at home in the evenings to strengthen his hip but evidently it was not enough.
“I’ve had a sore hip for a long time off and on, since I was 22 or 23, so it’s nothing new for me,” Murray said in his BBC Sport column after the first round.
“A couple of days after I played Stan Wawrinka at the French Open it felt pretty sore.”