The 25-year-old centre-back scored a first-half header on his first appearance for the national team in three years and helped clubmate Craig Gordon keep a clean sheet to raise the roof at Hampden Park as Scotland beat Denmark 2-0 to boost their World Cup prospects for Qatar 2022.
Souttar’s fourth cap came three years after his last Scotland appearance, when he was sent off against Israel in November 2018.
He has battled his way through a series of career threatening Achilles injuries since then, returning to fitness and form for Hearts this season and earning a late call up to Clarke’s squad last week.
The Scotland boss said: “John Souttar can be the story of the night for me. To come back from the injuries that John had over such a long period of time, it was a bonus, and I know how happy he was, just to be in the squad to get the chance to play.
“To play the way he played – and obviously the goal was the icing on the cake for him – His performance was outstanding as well.
“Congratulations to John. I gave him a big hug when he came off the pitch and it was quite emotional. You understand when you’ve been a player yourself and you’ve been involved in the game for so long how difficult it is on the road back.
“I’m absolutely delighted for John.”