Seven days on and Andy Murray, US Open finalist, appears all in white, not a whisker in sight, bright as a button and keen to knock on the head any thoughts that he and Jamie, his elder brother, have been involved in head-knocking of their own. As Britain requires that they both win a tennis match or two this weekend, this is comforting news.

The fourth-best tennis player in the world was at the David Lloyd Centre in Raynes Park, southwest London, to promote the “Road to Andy Murray” for five to 12-year-olds who have been banging heads all summer for the chance to compete in the competition final and meet the man himself. “It’s great to be around kids who just say whatever they feel - one of them told me I needed to smile more,” Murray said. And so he did.

He did get serious when the subject of brotherly love was advanced. Jamie left New York before the singles final, in which Andy was beaten by a rejuvenated Roger Federer, and stories percolated that the brothers had not been on speaking terms for the second time this year. Jamie was upset when Andy skipped the Davis Cup World Group first round in Argentina in February, when defeat consigned Great Britain to a play-off tie against Austria at Wimbledon this week to determine if they remain among the elite or return to the sport’s second tier.

So had they had a spat? “Every family has arguments, brothers and sisters fight sometimes and since Jamie and I were very young, we’ve fought and argued,” Murray said. “We are absolutely fine and come this weekend, it will be no problem whatsoever. I would like to think that people would respect family privacies. I don’t like to talk about this stuff and there’s no problem between Jamie and me just now.”

The most recent frostiness seemed to have carried over from their defeat in the doubles at the Olympic Games last month, when they won only four games in the second-round match against Arnaud Clément and Michael Llodra, of France. Their interview later was described as “icy”. “We’ve played doubles loads of times, some good, some not good,” Murray said. “I’ve heard that the Bryan brothers [Bob and Mike] have punched each other before now and they’re the best team in the world. It happens. I firmly believe Jamie and I should always play well together.”

Whether that is enough to get them the nod this weekend for what is likely to be the pivotal match on No 1 Court remains a delicate diplomatic act for John Lloyd, the captain, who knows more than most about placating aggressive kin because the majority of his 16 doubles appearances in the competition were with David, his elder brother. “Every time I play Davis Cup, I’ve enjoyed it because I get on well with all the others,” Murray said.

The Scot would have preferred the tie to be played on a hard court rather than grass because he is still favouring the right knee that gives him trouble from time to time - the injury flared a little during the US Open final at Flushing Meadows. Shifting from one surface to another and back again was the reason he opted out of the tie in February and when he was told that Marat Safin, the Russian, had withdrawn from the World Group semi-final in Buenos Aires, he did more than simply raise an eyebrow. “That’s terrible,” he said, tongue in freshly shaven cheek. “Are they [Russia] not playing in Argentina?”

Like all the leading players, he embraces the Davis Cup apart from when it interferes with his wider objective: to maintain the health and fitness levels he requires to remain at the top of the game. He did not realise that ranking points are on offer for the competition and does not agree with the concept anyway.

“I don’t think it works,” he said. “Can you imagine someone like Marcos Baghdatis, playing for Cyprus, knowing they will never make the World Group and he’s missing out on points that others can get every single year? And I don’t believe rankings points makes it easier to decide whether to play or not.”