It was not long, however, before the significance of their triumph set in. St Mirren have never won the League Cup and the meeting with Hearts on March 17 will be only their third appearance in the final. On the two previous occasions – against Aberdeen in 1955 and nine-man Rangers just three years ago – a general consensus emerged that they had been unfortunate to lose.
There will be a steely determination among Danny Lennon and his squad to ensure they do not depart Hampden nursing a similar sense of regret. Upon Celtic's exit, Hearts were immediately installed as the bookmakers' favourites to win the final, but there is little between the two teams that will now contest it, especially with the Edinburgh club hindered by a transfer embargo and in the midst of trying to drive down their wage bill.
St Mirren defeated Hearts in the semi-final on their way to winning the 1987 Scottish Cup and then again in the last four of the League Cup in 2010, and there is a feeling among their squad that they can now go on to make their own piece of history.
"Nobody remembers the losers in a final so we have to make the most of it," said David van Zanten, the defender. "We have a great opportunity, although Hearts will feel the same. It's a final and you're not playing one of the Old Firm so it will be pretty even, a flick of the coin really. We'll approach the game in the same way we approached [the Celtic game], confident that we can lift that trophy. We've worked so hard to get there it would be an awful shame if we don't do that now."
St Mirren's last two major cup final experiences could not have been more different. The legacy of the 1987 team can be seen the moment you walk through the front door at St Mirren Park, with photos of Ian Ferguson, Frank McGarvey, Kenny McDowall and the rest adorning every wall. In contrast, the loss in 2010 is spoken about in a whisper, the memory of losing a late goal to a short-handed Rangers team still a bitter one to those such as Graham Carey who went through it. "We see the photos of winning teams around the training ground and stadium, and we want our faces up there," said the Irishman. "[Beating Celtic] is a special achievement, especially after losing to Rangers a few years back. It was horrible not to go on and win that game.
"We probably didn't think we'd have another chance so soon but we have managed to get there. It was a great atmosphere at Hampden that day and I'm sure it will be exactly the same this time. We want to give the fans a trophy. We want to take the step and win the cup. There is still a lot of disappointment from the Rangers cup final defeat and we want to make up for it.
"We've learned a lot from that final. We didn't do enough on that occasion but we are determined not to make the same mistake. We will go for it in this final."
That last cup success 26 years ago – when Ferguson's extra-time winner ended Dundee United's resistance – became a motivational tool ahead of the win over Celtic. "We had a video in the dressing room on Saturday of the 1987 final," said John McGinn, the midfielder. "It showed us it could be done and we could beat Celtic. Nobody expected St Mirren to win the cup that season and it was a great inspiration to us against Celtic. Without that we might not have won."
Of their chances in the final, the 18-year-old added: "It could be anyone's game. It will come down to who wants it more on the day. We have a brilliant opportunity to go and lift a trophy."
Paul McGowan, whose penalty put St Mirren 2-1 ahead against his former club, was bullish about his team's prospects. "There's no reason now why we can't go on and win it," he said. "We don't fear anyone. We know how good we can be. If we play like that in the final I'm pretty sure we will come away with the cup."
Sunday's game was a milestone for Conor Newton, and not just because of his assist on Esmael Goncalves' opening goal. "That was actually my first 90 minutes in senior football," revealed the on-loan Newcastle United midfielder. "The win was absolutely magic, what dreams are made of."