Andy Murray leading the Great Britain team to Davis Cup success would be one of the greatest achievements in British sporting history, according to his former coach.
Britain take on Belgium in the showpiece final in Ghent over the last weekend in November, having not won the competition since 1936.
The British team were playing in the lower levels of the tournament only a few years ago but have improved massively under captain Leon Smith - largely thanks to the form of Murray.
The two-time major winner's former coach Mark Petchey praised the performances of the other GB players, but believes Murray can make the difference.
"Jamie Murray has played some wonderful doubles this year and there have been a few cameos by other players being able to get them through to the final, but if it hadn't been for Andy we wouldn't be in the final," Petchey said.
"For him to win it alongside his brother, I think it would be one of the greatest achievements by any British sportsman probably in history actually."
Murray started preparing for the Davis Cup final this week by practising on clay courts, but has the World Tour Finals in London to take part in before travelling to Belgium.
Petchey said: "I think he's doing the right things. His priority is Davis Cup. He would love to win the World Tour Finals and he's super competitive at everything he does, so if he steps on the court at the World Tour Finals he's going to want to win that match and do everything he can - it's as simple as that.
"I know he was hitting on the clay (on Monday) and one thing that is going to be difficult is the timing.
"We saw last year (Switzerland's Stan) Wawrinka and (Roger) Federer came late from the World Tour Finals for the Davis Cup final in France on clay and they played superbly well and won the trophy. It can be done and Andy is certainly of that calibre."
Petchey was speaking at St Brides Primary School in Cambuslang, South Lanarkshire, where he was coaching pupils to play with a 'Rebo' tennis wall installed at the school as part of a David Lloyd competition.
He was impressed with the standard of play and said: "With the interest they (the Murrays) have generated, for me, Scotland is the powerhouse of British tennis in terms of what I can feel of the love for the sport."