The first trophy on offer to the Murray brothers here fell into opposition hands yesterday, but the new territory trod by Jamie generated enough optimism around Flushing Meadows to believe that his younger brother may be about to deliver his family - and British tennis - a stunning reward this weekend.

Andy was indulging in the final round of media small talk before tomorrow’s semi-finals of the US Open men’s singles when Jamie was attempting to add the mixed doubles title to the one he collected at Wimbledon last year. It was to prove a forlorn task, as he and Liezel Huber, his American partner, were beaten 7-6, 6-4 in the final by Leander Paes, of India, and Cara Black, of Zimbabwe. Apt, somehow, that this was the weekend when the shutters went down on the latest instalment of Big Brother.

Although it is not in his nature, Jamie will be cursing himself, for it was his missed forehand volley on the second set point his team earned in the first-set tie-break that breathed life into Paes and Black. They had saved a first with an improbable intervention by Black on top of the net - a fluke, if truth be told - and secured the foothold in the final they never looked likely to give up.

Peter Curtis remains the last British player to have lifted the mixed title here, in 1968, the year when Virginia Wade secured the women’s title, a celebration of which she took part in on the opening night - the parade of champions from 40 years and one that Andy Murray watched with more than token curiosity.

“When you see all the winners of the US Open, you realise it is winning which really, really counts,” he said. “That’s what I’m going to try to do. Getting to the semis is a great achievement, but I want to go further. I don’t want to lose in the semi-finals."

To make good on that hope, he will have to defeat Rafael Nadal for the first time in six matches, the last but one of which, in the quarter-finals of Wimbledon, was a drubbing. It is not easy to get that one out of one’s mind, but from the first time they met, in the fourth round of the Australian Open in 2007, Murray believed that he belonged on the same court, there was no inferiority complex, and he felt his game was the Spaniard’s equal.

Never was there a better time to prove it. Nadal is about as vulnerable as he is likely to be - which means that he is a touch jaded from the exertion of winning all but two of the tournaments he has entered since April. He has said that he is not at his freshest, whereas Murray’s fitness levels have been at the cornerstone of the form he has shown on hard courts this summer. Having pocketed his first Masters Series title in Cincinnati, when he completed a second victory over Novak Djokovic, the world No 3, a forlorn trip to the Olympic Games has been all but forgotten in the heady anticipation generated by a first grand-slam semi-final.

Everything will need to go right for Murray, even to the extent that he will have to use the Hawk-Eye challenge system more wisely. His challenge record against Juan MartÍn Del Potro, of Argentina, in the quarter-finals was 12 erroneous challenges in 14.

His explanation is fascinating. “For me, 75 per cent of the time when I challenge, I do it on break points or big points where I just want to see where the ball was,” he said. “I don’t care if I get the challenges wrong, it makes no difference to me. It doesn’t change my attitude towards the way I want to challenge. I don’t just challenge because I think the ball is in. I want to see how far out it is. Or sometimes Hawk-Eye can be wrong.”

There may come a time in a huge match - and they do not come much bigger than a semi-final against the world No 1 - when a challenge can turn in a player’s favour and if you have used up your supply because you want to test the system, you are at a distinct disadvantage.

It is hard to imagine Nadal being profligate with calls simply to prove a point. He appreciates how hard he will have to work to defeat the British No 1 tomorrow. “It means nothing that this is his first [grand-slam] semi-final,” Nadal said. “I am not playing someone who doesn’t know how to deal with the situation. It’s true I have played more semi-finals than him, but he has had some important matches in his career and won them. He had problems with [Jürgen] Melzer and Del Potro was tough, but sometimes that can give you a lift."