THE subtext to this weekend's Davis Cup semi-final at the Emirates Arena turns out to a redemptive quest surrounding a self-styled wild child of the sport after all. It is just that the player in question is Dan Evans of Great Britain, and not Nick Kyrgios of Australia.

While the controversial 20-year-old with the diamond stud earrings cools his heels in his native Canberra, Evans, a lovable rogue and bon viveur of a Brummie who has combined unfettered brilliance with moments of madness during his career thus far, will attempt to harness those mercurial talents of his to fire Britain into their first Davis Cup final since 1978. It somehow said it all that the sudden promotion of this player who had originally planned to participate only in a Challenger event in Istanbul this week overshadowed even the rare pre-amble to Andy Murray participating in world class sporting action in his home city.

To say Evans is a wild card selection is to understate the case. As recently as June, when he narrowly failed to qualify for Wimbledon, this 25-year-old was ranked 763rd in the world. Even now, having showed an elusive burst of form to reel off 31 wins in 36 matches, enough to win two ITF Futures tournaments on home soil, come runner-up in two more and reach the semi-final of the Vancouver Open on the ATP Challenger Tour, he is still only the world's 300th best player, or the eighth-best in Britain. That puts him just behind Edward Corrie and just ahead of Joshua Milton in the UK ranks. Precisely.

Fifteen months have quietly passed since Evans last even went in against a top 100 player. But now he will face Bernard Tomic, the World No 23, in front of 8,000 supporters at the Emirates Arena. No wonder even the normally unflappable Aston Villa fan seemed rather bemused by his sudden ascension to the limelight.

"He [Leon Smith, the captain] asked me to come to be on standby and I said yes," said the 25-year-old of his sudden promotion. "Not a lot was said. He didn't even say Kyle had fallen, he just said someone was injured. It's a good opportunity to be around all the guys again, I haven't been in this environment for a while. I just came up for a practice really and things worked out a bit different."

Evans has enough hinterland to shake a stick at. A veteran of many a run-in with his one-time paymasters at the LTA, his funding was withdrawn after he visited a nightclub just hours before a boys' singles match at Wimbledon, briefly re-instated, then withdrawn again. Back in March he was fined £350 for failing to appear for a match, while Julien Hoferlin, his former coach, cited him as a prime exemplar of players coming through the British system who were "too spoilt".

If that is the downside, he also has so much upside. That was glimpsed back in the autum of 2003 when he put future US Open finalist Kei Nishikori to the sword in straight sets at the US Open before making short work of Bernard Tomic in the next round. The memory of that match, secured in four sets from 6-1, 3-0 down, is the main reason why Evans is where he is today. Evans hope the memory of that day also lingers with Tomic. The £60,000 he earned that week was half of his career earnings to that point. "My game matches up pretty well to him and that is what I have to do tomorrow, play that way," said Evans, "Everyone remembers when you have played someone before, I know I do when I’ve lost to someone. That’s always in someone’s head which is good."

Evans also has some previous when it comes to big wins on Scottish soil. He had the crowd eating out of his hand when he defeated Slovakian duo Lukas Lacko and Martin Klizan on Davis Cup duty at Braehead in 2012 while a crucial fifth rubber victory against Evgeny Donskoy of Russia sealed a 3-2 win in Coventry which which took Britain back to the World Group. "Coming back to Scotland is nice," he said. The atmosphere last time when I watched on television sounded very good and it was obviously better in the stadium. So yeah, I’m looking forward to it."

Evans' selection passed its first test at any rate - by throwing the Aussies on the back foot. "Yeah, we were all surprised," said Tomic, something of a reformed bad boy himself, having recently ended his exile from the Davis Cup team over a run-in between his father John and the Australian Tennis Federation. "Obviously they picked him for a reason - the fact he did beat me in the US. Honestly, I was up 6-1 and 3-0 up I think, and I couldn’t make a ball after that. That’s all I remember. It was a very, very windy day, he was very tough and very confident, he’d beat Nishikori prior to playing me so he was obviously playing well. I had a chance, I was comfortable and cruising, he started playing more free and he beat me. So it’s not an easy match – it’s tough for me."

These are the decisions which make and break Davis Cup captains and Wally Masur reckons Smith's decision to promote Evans ahead of James Ward and Kyle Edmund could define this tie. "Look, I think it’s interesting," said Masur. "As a captain, you make decisions based on what is right at the time. Then you get judged in hindsight. So, if Leon gets it right, he’ll be a genius. If he doesn’t, there will be people ready to stick it to him."