The full-back played the first-half of Scotland's victory over Denmark.
The 18-year-old played the first-half of Gordon Strachan's side's friendly against Denmark. And much like he has been at Parkhead this term, the youngster was excellent throughout.
He was able to deny Yussuf Poulsen the opportunity to equalise after Matt Ritchie had given the home side the lead, and generally showed the maturity of a player who has been on the international scene for several years.
And Gordon - who also put in a great display in the game at Hampden Park - heaped praise upon the defender due to his ability to make the step up.
"He had a hand in the goal and had a great clearance in the first half when the guy was straight through. That was vitally important to the win, if we lose a goal there it could have been a long night for us," he told the Evening Times.
"Kieran was a really important player at both ends of the pitch, but he's been fantastic all season. He continues to surprise, he is so calm and takes everything in his stride. Nothing seems to phase him at all.
"Whether it is coming in to the first team at Celtic at 17 and playing the same way he did right through his youth career, or doing it for Scotland.
"He's come up against really good players and he's handled that, along with everything else that has been thrown at him. It's great credit to him."
The performance is likely to give Ronny Deila plenty of confidence heading into the business end of the Scottish Premiership season.
While Tierney has established himself ahead of Emilio Izaguirre as the Hoops' first-choice left-back, he may have had concerns regarding whether the 18-year-old would be able to cope with the pressure of a title race that could well come down to the final games of the season.
However, having come through his international debut and earning rave reviews, it appears that Tierney will not only be a player that will be used regularly during the final weeks of the campaign but he will also be a player that the Norwegian can rely upon.