Wimbledon 2014: Andy Murray in muttering mystery as he crashes out to Grigor Dimitrov

Andy Murray appeared to have been unsettled by something shortly before his quarter final match at Wimbledon, which he lost in straight sets.

In the second set, Murray was heard muttering the words “shut the f*** up” to himself, while in the third, as he struggled to stay in the game, he said: “Five minutes before the f***ing match.”

After his defeat, the defending champion admitted that he had not got the start he would have liked. “My start to the match was poor. I started the match badly and I think that gave him confidence,” he said. “I should have done a better job at the beginning of the match of making it tougher for him, and I didn’t manage to do that.”

His opponent, Grigor Dimitrov, suggested after the game that he knew Murray would not be at his best from the moment they warmed up. “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.”

Murray’s spokesman Matt Gentry, who was sitting in the players’ box, said he had not heard Murray’s exasperated cries but admitted that the British number one had been “off his game”. He said: “He always mutters to himself. Occasionally his language is a bit colourful and he does talk to himself. I think they were utterances of frustration.”

Murray’s defeat adds to a disappointing summer of sport for the UK, coming after England were knocked out of the football World Cup in Brazil at the group stage – their earliest exit since 1958.

Stephen Heal, 39, from St Albans, who was watching from the stands at Centre Court today, said: “It was very sad and disappointing. It was as if Murray wasn’t trying. There was a sense of disappointment in the crowd. One bloke said: ‘He is just not in it’ and I think that is the way to put it.”

Politicians were also quick to pass on their commiserations after Murray’s loss. Scotland’s First Minister, Alex Salmond, wrote on Twitter: “Hard luck Andy. Roll on the US Open – definitely more grand slams to come!”

David Cameron’s official spokesman said: “Fans up and down the country will be disappointed but also looking forward to him bouncing back in future tournaments and at future Wimbledons. One of the things it points to is the strength in depth of the game in general.”