Armstrong popped up in overtime in Saturday's semi-final to score the winning goal against Nottingham Panthers, sealing a memorable come-from-behind 5-4 victory to set up Sunday's grand finale against the league champions.
It is a repeat of last year's play-off final which the Steelers won 6-5 in double overtime and Armstrong insists the South Yorkshire club can be celebrating again 12 months on - as long as they 'show up' and apply the same resolve shown in their last four encounter.
"Anything can happen in one game and that's why you just have to show up," said on Saturday night. "During the season you can have good nights and bad nights - but that just can't happen during play-offs, especially with the format we have here.
"We need everybody's A-game against Cardiff in the final - "if we get that, we can beat them."
Armstrong saluted the Steelers' resolve on Saturday evening, twice coming from from two goals down to sink Corey Neilson's team .
"Coming from behind like we did shows a lot about the character of this team," added Armstrong. "We showed that we could do it last year and a lot of the guys we have were here last year and we knew we could come back.
"It does kind of take energy away from you sometimes when you're a goal away, but you tell yourself youjust can do it. But when you're two down there is a second or two when you think it's going to be really hard.
"But it just shows the character of the guys coming back like we did. Levi scored another huge goal after Dowdy made a great play and that couldn't have come at a better time."