The Dons picked up their first piece of silverware in 19 years in Glasgow in March when 40,000 fans cheered them on to victory over Inverness in the Scottish League Cup final.
Victory over St Johnstone at Ibrox on Sunday will see them return to the city in May for the Scottish Cup final against Dundee United and Langfield says they are brimming with confidence ahead of the match.
"It is great to be in another semi-final," Langfield told REDTV. "Hopefully we can go out again and give a good account of ourselves and get back to Parkhead in May.
"It was an amazing occasion and for us to do that again for the fans would be an incredible achievement.
"We know though it is going to be a very difficult game against a very good side.
"But we have a squad now who believe we can win every game, not just semi-finals.
"On our day we feel we can beat anyone but we can also still have the odd blip now and again.
"So we are positive and fingers crossed we can get the right result, but as I say, we know how hard the game is going be."
Aberdeen beat Tommy Wright's side 4-0 in the Scottish League Cup semi-final at Tynecastle at the end of January and have won two and drawn one of their three meetings in the league.
However, Langfield is not reading anything into that record.
"St Johnstone are a very good side, I do not believe they get the credit they deserve," he added.
"For a number of years now they have been in the top six and this is their second semi-final this season.
"They have some players who can change games. For example Steven MacLean, who I rate very highly, and of course who we had here.
"They also have Stevie May who is scoring goals. The two of them link up very well together.
"So we are under no illusions how difficult it is going to be. We have played them enough this season to know what to expect.
"But when you get to a semi-final you have to grasp the opportunity.
"If things don't go right it won't be because of a lack of effort.
"As a team and a squad we will give it our all. We are very determined to win this game."