Leon Smith is an optimist by nature but the Great Britain captain has admitted that beating Russia in their Davis Cup tie this week would be "a fairly significant upset".

To most, it would be a minor miracle.

With Andy Murray preferring to practise for the clay-court season, Smith played a late hand yesterday when he named Dan Evans in the side to replace Scotland's Jamie Baker for the Euro-Africa Zone Group I second-round match.

Evans will play singles alongside James Ward, with Linlithgow's Colin Fleming partnering Wimbledon champion Jonny Marray in the doubles.

Victory would put Britain one win away from making it to the elite World Group for the first time since 2009 but if the task is not quite herculean – Mikhail Youzhny and Nikolay Davydenko are missing from the Russia team – on paper at least it looks beyond them.

In Dmitry Tursunov, Russia have a man who has tasted Davis Cup victory and who has worked his way back from injuries to a world ranking of 67. In Evgeny Donskoy, ranked 80, they have a hard-hitting newcomer who took a set off Murray when they met in Indian Wells last month.

In contrast, Britain do not have a player inside the world's top 200. Ward is at No.214, and Evans No.325.

Evans, aged 22, will begin the match today against Tursunov before Ward plays Donskoy. The doubles are tomorrow and the reverse singles on Sunday.

Fourteen months ago Evans enjoyed the best weekend of his career with two singles victories as a Murrayless Britain beat Slovakia 3-2 to get to the same stage.

It was hoped that might be the catalyst for Evans to kick on towards the top 100 but he has struggled to make any inroads at elite level and Smith admitted he was taking a leap of faith in naming him above Baker, who he had originally chosen for the tie.

"It was a really tough decision," Smith said. "All the players are pretty evenly balanced, obviously outside Andy. Thinking about the court speed, the environment and the match-ups against the Russians, it was my gut feeling that Dan had a slight edge over Jamie. What Dan did last year in Davis Cup, when he really rose to the challenge and put in excellent performances against Slovakia and Belgium, is still fairly fresh in the memory."

Smith gave no other reasons as to why he should leave out Baker but the Scot has also struggled to make progress since he began the year by qualifying for the Australian Open.

Injuries and illness have again played a part but, having tried to qualify for some ATP Tour events, Baker did not earn the victories he needed and has been forced to drop back to Challenger Tour level again.

In Fleming and Marray, Britain will be confident of getting a point in the doubles but will need Ward and Evans to produce something special.

Murray has committed to play the in September tie but unless the miracle happens, it is more likely to be a relegation battle than a promotion chance.