IN his three years as an Edinburgh player, Jaco van der Walt has met every challenge head on and emerged as a more mature and well-rounded athlete. Tomorrow, however, the 26-year-old stand-off will face by far his biggest challenge yet as he lines up to make his Scotland debut opposite Ireland’s Johnny Sexton.

The South African, who only qualified to represent his adoptive country on residence grounds late last month, is one of six changes made by Gregor Townsend to his starting line-up for the Autumn Nations Cup third-place play-off in Dublin. But the other five - Darcy Graham and Duncan Taylor in the backs, Rory Sutherland, Zander Fagerson and Blade Thomson up front - are known quantities at this level.

The selection of Van der Walt, then, represents a calculated risk, yet one that the head coach believes is well worth taking. Duncan Weir deputised more than adequately for the injured Finn Russell and Adam Hastings in Scotland’s last two games, but the Worcester man is a known quantity. Time to try something different.

“This year and last year he’s taken his game to another level,” Townsend said of the debutant in waiting. “Defensively, he must be one of the best tackling stand-offs in world rugby.

“His passing and kicking are at a high level and he’ll be looking at ways to best influence the defence. It will be just that little bit quicker at international level, but we have a real belief and faith in his ability and in those around him to bring the best out of our backline this weekend.”

With two other South Africans, Oli Kebble and Duhan van der Merwe, having already made their Scotland debuts this autumn after qualifying on the residence rule, the selection of Van der Walt has inevitably rekindled the debate about the value of imports versus homegrown players.

Townsend defended his choice of those three and others who have been capped under the same rule, but also insisted that we had become better than before at producing players ourselves, citing the presence of three Hawick men in his team - Sutherland, Graham and captain Stuart Hogg - as an example.

“Jaco’s been playing for Edinburgh the last three years and his play and performances have earned him the right to be considered,” the coach went on.

“He’s a very humble and hard-working player, puts his body on the line and he’s a great defender. And his great-grandfather is from Aberdeen, so there is a Scottish connection.

“But that’s not necessary. We know the rules that other countries as well as ourselves have used. Those players that get capped through those residency mechanisms make a huge effort to play for that country. That’s what we’ve seen with Duhan and Oli, and we’ve seen in the past from WP Nel and Sam Johnson.

“I believe we’re producing players better than we’ve ever done before. We don’t have anything like the player numbers of any nation in the top 15 in the world - Italy and all those countries have many more players than us. So we have to work very hard at getting players to the highest level.

“Our depth’s at the best ever level. There’s players who have come through residency in that, but that’s always been the case over the years.

“The real pleasing aspect is we have three players from a small town in the Borders who are all starting for Scotland. That’s not happened in the pro era. Those who said rugby would struggle in the Borders in the pro era and the loss of the Borders pro team, here’s three guys who didn’t play for the Borders because it didn’t exist and now they’re playing for Scotland. That’s a real success story.”

While claiming a rare win in Ireland would be an excellent way for Scotland to end their year, the more enduring success story from this autumn as Townsend sees it will be the increasing depth and experience of the squad. As the coach pointed out, Van der Walt will be the fifth man to play at stand-off this autumn counting Hogg’s brief stint in the position against Wales, while other selections too have been designed to increase internal competition.

The return of Thomson at blindside rather than No. 8, for example, allows Jamie Ritchie to move over to openside in place of the rested Hamish Watson. Blair Cowan, meanwhile, will win his first cap in four years if he comes off the bench and takes over from Ritchie. And, with Blair Kinghorn having been ruled out by a broken finger, Huw Jones is back in the squad as back-three cover.

Scotland (v Ireland at the Aviva Stadium, tomorrow [Sat] 2.15pm): S Hogg (captain, Exeter); D Graham (Edinburgh), C Harris (Gloucester), D Taylor (Saracens), D van der Merwe (Edinburgh); J van der Walt (Edinburgh), A Price (Glasgow); R Sutherland (Edinburgh), F Brown (Glasgow), Z Fagerson (Glasgow), S Cummings (Glasgow), J Gray (Exeter), B Thomson (Scarlets), J Ritchie (Edinburgh), M Fagerson (Glasgow). Substitutes: S McInally (Edinburgh), O Kebble (Glasgow), W Nel (Edinburgh), S Skinner (Exeter), B Cowan (London Irish), S Hidalgo-Clyne (Exeter), H Jones (Glasgow), S Maitland (Saracens).