In the end the goal was not enough to give Scot Gemmill’s men victory as their Icelandic opponents hit back twice in the second half but it was another important step in Johnston’s development as he looks to emulate the career success enjoyed by his dad, Allan.
The former Hearts, Sunderland, and Rangers winger, who also counts Kilmarnock and Queen of the South among the clubs he has played for and has subsequently managed, was in the stand as the 18-year-old stepped up from the Under-19s and proved himself capable of playing at the higher level.
"I've watched the videos of him on YouTube. He was a tricky winger and that's definitely not me! But he's got all his caps and his strips in the house and it has always been a really good inspiration to me growing up seeing all his strips and that. Watching his videos back, I've always wanted to be just like him.”
And, while some would be daunted by the prospect of having to live up to high standards, the Motherwell right-back, who is currently shining on loan at Cove Rangers after a loan spell under his dad at Palmerston Park, says that being able to tap into that knowledge and expertise has always been a positive.
"We've worked on being a winger and a full back. He's told me better ways to defend against tricky wingers. He has always helped me and encouraged me. I was buzzing to score in front of him and my mum. It was really good for them to see it.
“It was a huge honour for me to play for the 21s. He just said to go and do my thing. He believes in me and told me to just go and do what I am good at. He's been a huge influence in my career. I have been really lucky to have someone like him growing up. He was always training with me even in the close season and last season he gave me a lot of game time at Queen of the South too. He's been really good for me and I am grateful for all he has done for me.”
The goal against Iceland is one his dad would have been proud of. Initiating the move, he bombed upfield, slipping the ball into Liverpool teenager Ben Doak before continuing his run and ensuring that when Doak got to the goalline and looked up he was there to smash home the cutback.
“That was the first time I have played with him and you could see he is a really good player,” said the Championship defender of the Anfield breakthrough star. “The combinations were good and we were working together in training. I was really happy to get a goal, but it was disappointing to lose. I thought we played quite well in the first half and we missed a few chances. But in the second half they came out flying the first 20 minutes and they battered us. We will look back and see what we can do better."