The analogy offered by Scotland assistant manager Mark McGhee, however, is fully intended as nothing less than the most glowing of compliments to the country’s most exciting young talent.
In the fearlessness and resilience of the Celtic left-back, who started the week of his 20th birthday being fitted for a gumshield which will allow him to play on despite the broken jaw he suffered in the Scottish Cup final 12 days ago, McGhee sees strong similarities with former England star Stuart Pearce.
As Tierney prepares to win his fourth cap for Scotland in Saturday’s crucial World Cup qualifier against the English at Hampden, McGhee feels the Tartan Army may come to savour their very own ‘Psycho’.
“Stuart Pearce is a good example when you talk about what Kieran has,” said McGhee. “You think about playing with that blood on the face and head, or whatever, and that is Kieran. That’s the way you expect him to be, with his determination and aggression. He might not intimidate people yet, like Pearce did, because they don’t know him well enough. But in time Kieran will be a player who, simply by playing against him, players will be intimidated.
“He is definitely one who grows, even in terms of his physical stature, whenever he crosses the white line to play.
“You see him round the training camp and he is just going around quietly, with his duffle bag on his back. I don’t know what he keeps in it. His boots probably – and his gumshield now! But when he takes that off and walks on to the pitch he is a different animal.
“He has been throwing himself into challenges as usual this week, he’s fearless. You’ve got to hold him back at times. He is one of these boys who only knows one way to play – and that includes training. I don’t think he has a second gear he trains at before shifting up for games. He trains the way he plays.
“He got his gumshield measured Monday morning and delivered. It’s the same dentist who treated him after the cup final and he’s happy with it. He wore it this morning, he has two, and he wore one at training. He says he finds it difficult to shout, but otherwise no problems.
“He’ll get used to it and I’m quite sure he will find a way of communicating. I’m not 100 per cent sure he’s a lad who says that much to anybody, anyway. So I don’t see that as an issue.”
McGhee also feels Tierney benefits from having an uncompromising role model much closer to home in the shape of Celtic and Scotland captain Scott Brown.
“He seems to mimic so much of Browny,” added McGhee. “He comes to training in all weathers in short-sleeved shirt and shorts. I think he feels the pressure of Browny being like that and thinks ‘Well, if he’s not wearing a long-sleeve jersey, I can’t either’. I don’t know if he wants to wear one. But he has that kind of toughness where he tests himself all the time. That’s what I like about him – he always seems to be testing himself in all sorts of ways. That is reflected in the way he plays.”
As he did with such assurance in the 1-0 win over Slovenia in March, Tierney is set to switch flanks to play in the problems position of right-back for the Scots on Saturday evening.
“He did brilliantly at right-back,” said McGhee. “He might have surprised a lot of people. We weren’t surprised but we were pleased. We didn’t necessarily know any more than you did about how he would look. The manager spoke to Brendan Rodgers at Celtic, got his thoughts, and everybody was confident the boy was a good enough player to carry it off. He proved that.
“Whether he is going to be asked to do that again has yet to be decided, but we would be confident that he would make a good fist of it if he was asked to play there. It’s a great bonus because we are short of right-backs. We’ve asked Ikechi Anya to play there and we don’t have a lot of other right-backs to call upon.
“We have left-backs – but that’s a problem as well, because we have Kieran, Andy Robertson and Stephen Kingsley, who is playing at a high level fairly regularly and is a good player as well. So we have a lot of riches there and they can’t all play. We probably won’t ask the full-backs to be more defensive against England. We were happy with the way they got up to Slovenia and closed them down. Kieran has great recovery as well, so we will ask him to play his natural game and not put any artificial reins on him.”
Already on the radar of English Premier League clubs, Tierney’s wider profile beyond Scotland could be significantly enhanced by another impressive display in such an important fixture.
“There’s no real pressure on him, because I don’t think he will pay much attention to what’s being said about him,” said McGhee. “He won’t believe what anyone says. He will just get on with his job. Therefore it’s an opportunity for him – and he probably doesn’t realise this – to show just how good a player he is.”