Scotland, on the other hand, failed to take any of the chances they created and now head to Wembley on Friday needing a result.
“We need to take the experiences of today, learn from what happened, and make a few little tweaks to our game,” Southampton midfielder Armstrong told the BBC.
“Fundamentally there were some positive moments and we have to carry that through to Friday. We’ve got two chances to produce a good performance and get something from it.
“It was a difficult one, the game was very compact, there wasn’t much space, and we were playing too many long balls for our liking.
“When we passed it, we did quite well but it was hard to break them down.
“[We’re] disappointed with the way the first goal went in, apart from that we defended pretty well, and they showed real quality for the second goal.
“Not to say we didn’t have chances in the second half, we did, and tried to push. They were clinical. At this level you do need to be clinical.”