Celtic missed the Champions League group stages the last two years.
Celtic beat Hapoel Beer Sheva in the playoffs in August to book their place in the group stages for the first time since 2013.
It was an excellent start to life as Hoops manager by Brendan Rodgers, who replaced the Norwegian back in May.
Under Deila, Celtic fell short of the group stages, and with it the huge financial windfall, in his two seasons in charge at Paradise, but normal service has been resumed under the Northern Irishman.
Rodgers's side host Borussia Monchengladbach at Parkhead on Wednesday as they chase a first win in the competition, having held Manchester City to a hugely-entertaining 3-3 draw last time out, after being demolished 7-0 at Barcelona in the Group C curtain raiser.
And Armstrong says that every Celtic player is determined to make the most of their opportunity in Europe's elite competition this time around.
“There are huge pressures here but I think that is a positive thing,” he said to the GET.
“When I was first here under Ronny [Deila] there was huge disappointment when we didn’t reach the group stages of the Champions League because the feeling was that the club should be in there at that level.
“Now we are here and we want to go and acquit ourselves well against some of the best teams in Europe. I think especially here at Celtic Park we are a match for anyone and there is no doubt that every player in our dressing room is hungry to not just play but play well at this level.”
Celtic's Stuart Armstrong celebrates after scoring their second goal