Andy Murray's mother has said she is not aware of her son suffering any distractions before his straight sets defeat to Grigor Dimitrov at Wimbledon.
The Scot had hardly put a foot wrong in his first four matches, but he never approached his best tennis against the Bulgarian.
During the game, Murray, 27, was spotted by some onlookers swearing in the direction of the players' box, and reportedly shouted: "Five minutes before the f****** match."
When asked if Murray had been distracted by anything before the match, his mother, Judy, said: "No, not that I'm aware of."
She told BBC Radio 5 Live: "I think every athlete can handle losing if they've played well or played their best and I think when you're on such a big stage as this and especially when you're defending your title and it's in front of your home crowd, I think it is so difficult to take that you haven't managed to find close to your best form."
Dimitrov suggested after the game that he knew from the warm-up that Murray would not be at his best.
"I think it's just a feeling," he said. "I have practised quite a few times with him and I know how he is striking the ball when he is at his best, I know how he is playing when he is not at his best. I think it's just a feeling that I had."
It is not clear what Murray's outburst referred to, although his match did start earlier than normal.
Play began on Centre Court at noon rather than the usual time of 1pm to catch up with the schedule after rain delays, and the match before Murray's ended after just 57 minutes.
Writing in his BBC column, Murray said: "There was nothing different in the build-up and no reason to expect that kind of performance.
"The timings changed a bit because we played the quarter-final pretty early compared with some of my other matches, but my routine was the same and I practised with James Ward both days."
A spokesman for the All England Club said the procedures for starting Murray's match were "no different to normal".
Murray's spokesman, Matt Gentry, was sitting in the players' box and said he did not hear his outburst.
But he added: "Occasionally his language is a bit colourful and he does talk to himself.
"He does look at the box - he likes to see people he knows rather than a face in the crowd. I think they were utterances of frustration. It would have been just frustration, to be honest with you.
"He was quite circumspect after the match."
Murray revealed he would now go back to Miami to work hard in training.
"The game always improves and gets better, and I know I have things to work on. I plan to be back on the practice court and in the gym soon," he said.
The spotlight moved to the ladies' singles today with both semi-finals taking place on Centre Court.
In the Royal Box actor Colin Firth was spotted chatting to TV presenter Cilla Black and singer Sir Cliff Richard, while comedian Miranda Hart sat next to actor Eddie Redmayne.
Broadcaster Sir Michael Parkinson and his wife, Lady Mary, were also in the exclusive enclosure, along with swimmer Ian Thorpe.
The Centre Court crowd watched former champion Petra Kvitova beat fellow Czech Lucie Safarova before Canadian Eugenie Bouchard took on Simona Halep.
Play was suspended for a few minutes during the second match when an elderly spectator fell ill.
She was helped out of the stand by St John Ambulance staff.
Murray's brother, Jamie, is also in action on the showpiece court in the third round of the mixed doubles.
It is a dry, bright and warm day at the All England Club, with temperatures expected to reach a maximum of 27C (81F).