Andy and Jamie Murray - who calls the shots?

Jamie, 29, and Andy, 28, are almost certain to play together in the all-important doubles rubber on Saturday. The tie might well turn on their pairing on the red, indoor clay court in Ghent. Win and Britain could be celebrating their first Davis Cup in living memory.

Jamie may be the eldest, but bossing the doubles court has little or nothing to do with being the firstborn. There aren’t many places where Andy, who has two grand slam titles and an Olympic gold medal, takes direction, but he recognises that the doubles court is Jamie’s territory. Jamie is one of the world’s most accomplished doubles players: a Wimbledon champion in 2007 with Jelena Jankovic in the mixed doubles, and a finalist at both Wimbledon and the US Open this year with his partner, Australia’s John Peers.

Casual in combat pants and sweatshirt in the London offices of his management company, Jamie acknowledges that he will be in charge when playing the Belgians, at least “most of the time”. He explains: “Andy likes to call his own serves, which is fine. I lead a bit more with the team energy and everything, because I’m used to doing that when playing doubles.”

One of Jamie’s priorities will be to reassure his kid brother. “Obviously, when Andy’s playing singles, he’s only playing for himself,’ Jamie says. “I guess I’m giving him some security, making sure we’re always showing positive energy. Maybe he’s missed a shot, and I’ll be letting him know I still trust him. That’s not something that’s natural to him, as you don’t do that in singles, where it’s all about the individual. But in doubles you have to do what’s best for the team.”

Twice already this year – against France in the quarter-final and Australia in the semi-final in Glasgow – the brothers have won the doubles. As Andy said after their pulsating five-set victory over Australia’s Lleyton Hewitt and Sam Groth, “we stuck together, as brothers should”. And when Jamie and Andy found themselves shouting at each other in Glasgow, it was only because they had to make themselves heard.

Jamie and Andy Murray in 2005

In the white heat and excitable atmosphere of the Davis Cup, when “it’s so loud it’s a joke”, Jamie is reassured by having a member of his family alongside him. “It’s nice to look across and see your brother there. We both know that the other will be doing everything he can to win, and that you have the same goal and the same desire,” Jamie says. “From a tennis point of view, Andy’s such a great player, and he’s been in those kind of situations so many times, that you don’t need to worry about whether he’s going to hold up under the pressure and in that really intense atmosphere. He has already experienced so much. That’s a great thing that I don’t have to worry about him, as it gives me confidence to go and do what I need to do.

“Andy and I, our careers have been different. We’ve had our own paths. He’s had an amazing career, far better than anything I’ll ever achieve, but I’ve still been able to get to the top of the game and play against the best players in the world,” says Jamie, and he’s certainly not jealous of his brother. Although he’s happy to tease their mother, Judy Murray. When she tweeted a picture of Jose Mourinho and Andy with the caption: “The Special One and My Special One” earlier this year, Jamie replied drolly, “thanks Mum”. Judy swiftly described her first child as “My Extra Special One”. But Jamie insists no damage was done.

Perhaps many older brothers would be envious of a younger brother who has had greater success in the same profes sion. Over the course of his career, Andy has earned more than $40 million in prize money, and many times that in sponsorship deals and appearance fees. He has homes in Surrey and Miami, and other properties including a hotel outside Dunblane. Jamie, meanwhile, has earned less than $2 million in prize money, has profited considerably less from endorsements and lives in a flat in Wimbledon.

Jamie Murray with Alejandra Gutierrez

But there’s no envy whatsoever on Jamie’s part, and the closeness of the brothers’ relationship is demonstrated by each being best man at the other’s wedding. The first to wed was Jamie, who in 2010 married Alejandra Gutierrez, a Colombian who now works in the marketing department of a data company. Earlier this year, Andy married Kim Sears (below) and they’re expecting their first child soon.

Jamie is the softer and sunnier of the two: he has said before now that “A few people would say Andy should lighten up and I should be more nasty.” But some say it was Jamie who enabled Andy to become the cussed, hardened competitor he is today. If Andy hadn’t had an older brother who played tennis – someone who was always around to practise with and compete against – he arguably wouldn’t have developed the lust for competition that has driven him to the top of the sport.

Of all the rivalries that Andy has had in his tennis life – and he has won and lost against the likes of Roger Federer, Rafa Nadal and Novak Djokovic on the biggest stages – few, if any, have been as intense as the one he had with his brother at the local club in Dunblane. In return, Andy has helped and encouraged Jamie, and is protective of his older brother – he once accused the Lawn Tennis Association of having “ruined” his sibling as a youngster.

No one today would suggest that Jamie is in any way “ruined” as a tennis player. For all his other achievements this year – including appearing in those two grand slam finals – Jamie has found that the public mostly want to talk about the Davis Cup. “Sometimes I get recognised on the Tube or on the bus. Yesterday I was on the bus and someone asked for a selfie. If you start winning, people take notice a bit more. A lot of people come up and want to talk about the Davis Cup. It’s cool because the Davis Cup reaches a different audience to regular tournaments. I think at first I didn’t quite grasp what a big achievement it is getting to a Davis Cup final, and how far-reaching it is,” Jamie says.

“The doubles at a Davis Cup tie is played on Saturday afternoon and I guess there are a lot of people who are at home watching on TV. The match against Australia was an epic match, such an amazing match with so many ups and downs. I was enjoying playing in it, and I think for the spectators and for anyone watching on television, it would have been really exciting.”

Judy Murray with her sons

This weekend in Ghent is likely to be an agonising experience for Jamie and Andy’s parents, Will and Judy. “My mum gets quite animated whenever we play, and I’m sure the Davis Cup will be no different. My dad is a bit calmer, or maybe it’s just that he doesn’t show it when he gets agitated,” Jamie says. “I’m sure it will be stressful for them. But they will be very proud to see Andy and me out there playing together in a Davis Cup final.”

There’s a Monty Python sketch in which Scotland is described as “the worst tennis nation on earth”. How dated that looks, now one family from Stirling has collected all of Britain’s points in the quarter- and semi-final. If that happens again in the final in Ghent, some might say Dunblane has won the Davis Cup.

“It’s been a long journey from when we played together in Dunblane to playing in a Davis Cup final together. I’m sure that Mum and Dad never would have imagined that we would go on to do what we’ve done. It certainly wasn’t expected. We’ve both been on great journeys, and have been leading great lives.” And now for Murray major, as well as Murray minor, tennis greatness awaits.

Mark Hodgkinson is the author of Game, Set and Match: Secret Weapons of the World’s Top Tennis Players (Bloomsbury)

The Davis Cup continues on BBC1 this Saturday at 2.05pm and on BBC2 this Sunday at 11.50am