Leon Smith has hailed Jamie Murray's contribution to Great Britain's Davis Cup run ahead of the final against Belgium.

The doubles specialist had not played for Britain for almost four years when he was selected for March's first-round match against the USA.

Murray showed his improved form as he and Dominic Inglot almost pulled off a stunning comeback against Bob and Mike Bryan, but it is with brother Andy that he has really shone.

A week after reaching the Wimbledon final with Australian partner John Peers, Jamie was the standout player as he and Andy defeated the French at Queen's Club.

And on home soil in Glasgow in September, just after Jamie and Peers had made the final of the US Open, the Murray brothers won in five pulsating sets against Australians Lleyton Hewitt and Sam Groth.

British captain Smith said of Jamie's form: "It's absolutely fantastic. The doubles rubber is always key and we've always been spolit for choice, but in Jamie we have one of the best players in the world now, and that makes a big difference.

"When you look back to the tie against France, he played unbelievable tennis. It was like a man on fire. And he's kept that going. This means an awful lot to both brothers, not just Andy."

Whoever Belgium play in the doubles rubber, with Steve Darcis and Ruben Bemelmans the favourites, it is tough to make a case for the hosts winning it.

The same can be said for both of Andy Murray's singles matches, so they will have to cause a big upset somewhere if they are to deny Britain a first Davis Cup title since 1936.

The big factor in Belgium's favour is that they are playing at home, as they have throughout their unexpected run to the final.

The indoor clay surface would certainly not be what Britain would have chosen while 13,000 fans, 90 per cent of them Belgians, will be packed into the Flanders Expo.

Smith has only lost two ties since taking over as captain in 2010. One was against Belgium in Glasgow in 2012, when Andy Murray did not play, while the other came last year on clay in Italy.

He has also masterminded away victories on clay in Croatia and the USA, and Smith said: "There's not a huge amount you can change in terms of your preparation in dealing with the fans that are going to be there.

"We've played in front of our fans to know what the atmosphere is like when it's been on our side. Obviously you'll flip it the other way.

"We've had experience playing in Naples and Umag, as well, which were good atmospheres. San Diego was a bit quieter.

"Our team's got a lot of experience now because of the ties. It's more about preparing for the matches, as everything has been pretty well documented, the training that everyone has done.

"It's been slightly different for each player, but it's all been geared towards the surface and environment here."

The ATP World Tour Finals in London on hard courts was a complicating factor for both the Murray brothers but they practised on clay both before and after the tournament at the O2.

Meanwhile, Kyle Edmund and James Ward, who are competing for the second singles spot, travelled to South America to play tournaments on outdoor clay.

Ward returned home a week before travelling to Ghent but, having won a title in Buenos Aires to put himself in pole position to play against Belgium, Edmund stayed on to play a tournament in Montevideo.

He only arrived back in Britain on Saturday but is confident it will not adversely affect him.

He said: "Throughout the year we're having to deal with jetlag and travel. We find ways in ourselves to deal with that. It's no different this time. I know what I need to do to get my body in the best shape if I'm going to play.

"I feel fine. It's obviously helped me physically to go to South America and play on the clay."

Smith must name his final four-man team an hour before the draw on Thursday afternoon.