"It is something I've always dreamed about and to do it was an incredible feeling."

Galbraith entered the fray alongside Rangers midfielder Steven Davis, whose late cameo saw him equal Aaron Hughes' outfield record of 112 caps for Northern Ireland, as two different generations came together.

"That was unreal," Galbraith added. "Even just to stand beside him was crazy. I have looked up to Steven Davis since I've been a kid with him being Northern Ireland captain.

"He has always been one of my favourite players and I would say he is the player I look up to most since I was growing up for what he has achieved in his career."

O'Neill had said it was a particularly nice moment to introduce Galbraith alongside Davis and wants the teenager to use the experience to his advantage.

"Ethan we've known since he was a baby," O'Neill said. "Since the age of 13 he's been in the system and it's lovely to give a kid that opportunity.

"He's come into training and he's a lovely player, so easy on the eye.

"Hopefully that will give him the motivation and focus to kick on with his career."

Galbraith was one of several youngsters to get their chance on Thursday night, with Ciaron Brown and Alfie McCalmont also making their debuts, while there were second caps for Shayne Lavery, Liam Donnelly and Tom Flanagan.

Lavery looked particularly impressive as he got on for the final half-an-hour and added energy and impetus up front, seeing one shot brush the side-netting while setting up an excellent chance which Donnelly sent over.

"I really enjoyed it," said the 20-year-old, who joined Linfield this season after four years with Everton and has thrived on the back of regular football under David Healy.

"I didn't think I'd get 25-30 minutes but I really enjoyed it.

"I did say if I got on I'd run about and the gaffer said to me to just try to nick it off defenders and run in behind and I think I did that.

"When I hit the side-netting I probably should have tried to pull it back towards Gavin (Whyte) or JT (Jordan Thompson) because it was a very tight angle which I just realised when I did shoot."

While the desire to keep players fresh to face Germany was key to so many youngsters being involved, Lavery said it is part of a pathway that O'Neill has laid out to them.

"Michael said to the under-21s we are not that far away from the senior squad and, with the likes of Ethan and Bobby Burns coming up, too, it's nice that he's always looking at the under-21 players," he said.

"We had a really good campaign last time with Liam Donnelly and Mark Sykes and all. And I think this squad of under-21 players can be a step up again.

"Playing in games like this gives you a taste for more. That's why Michael has brought so many players up to show we aren't that far away."