The link-up between the black and whites from either side of the border - originally fostered by Saints assistant and former Newcastle coach Tommy Craig - made Conor Newton and new boy Adam Campbell the most popular Geordie duo in Paisley this side of Ant and Dec. Not only that, but left-back Paul Dummett earned a long-term deal in the Newcastle first-team squad on the strength of a loan spell at St Mirren Park last season.
As the junior partner, St Mirren can only be enhanced by the arrangement, but just occasionally their interests must play second fiddle to those of the giants of the Barclays Premier League. Right now, for instance, at precisely the same time as the Paisley club are welcoming diminutive striker Campbell to the fold, they are also fretting over Newton, whose loan deal is currently due to expire in the middle of this month. While the two parties have a provisional agreement to extend that until the summer - when Newton's Newcastle contract also expires - the big fear is that Alan Pardew, with great chunks of the French international squad currently cluttering his midfield ranks, will decide against offering the young player a new contract and instead sell up, rendering him available to bigger clubs in the food chain, either in Scotland or in the Championship.
It would certainly be surprising if there was no serious outside interest in the player, so reliable has he proved in the last 12 months on loan in Paisley, a spell in which he helped overcome Celtic on his second start for the club during last year's League Cup semi-final, not to mention the clinching strike in the final which took such long-awaited silverware back to the club. Newton would love to stay, but isn't entirely sure whether he is coming or going.
"I am not 100% sure yet but I think that I will stay," he said. "They are my thoughts on the matter. In this game you never know what is round the corner. So that is part of my thinking as well, do I want to be going elsewhere in January, trying to break into another squad in the last six months of my deal? Maybe not. Maybe I just want to get as many games as I can.
"I haven't heard anything about an extension at Newcastle yet," added the player, an acquaintance of Celtic's Fraser Forster from their time at St James' Park. "But touch wood. They have got a massive budget because they are a massive club. You just have to treat that with respect and try your hardest to get people to look at you, which is what I am trying to do."
It certainly didn't take long for Newton to have observers sitting up and taking notice last season. The appearance in that 3-2 Hampden victory last January was only his second senior start, and many who saw the game will remember the way in which he effortlessly rode a crashing tackle from Celtic's Victor Wanyama. The task in hand today is no less arduous, as St Mirren attempt to become the first SPFL Premiership side to inflict defeat on the Parkhead side.
"It would be nice if history could repeat itself," said Newton. "We probably are bigger underdogs this time, but you are always underdogs against a team like Celtic. You just have to go out and try to upset them, try and do what you do best and stop what they do best."
This time, though, it is Campbell and not Newton who is the unknown Geordie quantity in the St Mirren ranks. Newton gushes about the 19-year-old's talents, which saw him represent England at youth level and follow in the footsteps of Carlos Tevez, Andres Iniesta and Fernando Torres by being named MVP at the prestigious Nike Premier Cup at Old Trafford.
"I had a word with him and said coming here would be good for his progression," said Newton. "It is a good move for him - I think he is going to get a lot of goals up here. He was very good in the youth set-up at Newcastle, he won lots of awards, like the MVP at the Nike Cup that teams from all over Europe go in for," Newton added. "There are some big names on that trophy. So he is doing well, but coming up here and getting games is the only way he is going to make it."
One man who won't be on the field today is Jim Goodwin. The St Mirren skipper - who has played for, and has had his run-ins with, Celtic - is serving the second match of his suspension for that infamous forearm smash on Dundee United's Stuart Armstrong. Manager Danny Lennon admitted the player's indiscipline is a subject of internal discussions, but said the player was more sinned against than sinning.
"There's no doubt other clubs specifically go out there and target him," said Lennon. "There are managers and coaches out there who have a go at the fourth official or the linesman from Jim's first challenge in every game, even when he's won the ball cleanly and fairly. We know that happens, but I like to think we have good referees who aren't naive enough to fall for that week in and week out."