Armstrong’s first European experience with Ronny Deila’s men after signing from Dundee United was in February’s astonishing 3-3 draw with old foes Inter Milan at Parkhead in the last 32 of the Europa League.
Although the Italians won the return 1-0 in the San Siro, he believes the experience of playing such a big club stands him and the rest of the squad in good stead for whoever stands between them and the Champions League group stage.
Armstrong said: “Those games against Inter were a good experience for me and the squad – to know we can play well in those big ties.
“And we’re optimistic and excited about the next round and hope to achieve the ultimate goal and get into the group stages.
“It was a tough game against Qarabag. We knew they had to come out and do something to get back into the tie and we were happy to keep our shape and play on the counter.
“I thought it was very well played by ourselves. It was tough and tiring and it was nice to have the water breaks.
“So, it was a very challenging night both physically and mentally, but you could see the emotion on our faces when the final whistle went, we were all delighted.”