A Liam Harvey hat-trick was the highlight of an end-to-end Cup tie which saw the Visitors edge out their hosts in a seven goal thriller played in bitterly cold and latterly near farcical conditions as the gales hit Paisley in the latter stages.
The young Dons travelled to Paisley looking to reverse a run of three league defeats as they took on the Buddies kids with a quarter final place in this season's Youth Cup awaiting the victors.
After Blessing Oluyemi had been forced to save well in the opening minute, Aberdeen took the lead in only the second minute. Picking up a short pass from his keeper, Ethan Duncalf played a delightful ball over the top for Liam Harvey to race on to, the striker netting with a delightful lob over the outrushing Kennedy.
Skipper Evan Towler showed all his class with a wonderful block on the penalty spot to deny Saints an equaliser before Barry Robson's babes doubled their lead on ten minutes. Great pressing from the Dons, particularly from the impressive Finn Yeats, forced an error and Harvey clipped the loose ball over the keeper to take his Youth Cup tally to four this season. Two fine finishes from the bustling hitman.
The young Buddies weren't lying down though, and they reduced the deficit on 25 minutes when Keiran Offord, their most dangerous looking forward, cutting in from the left, engineered a shooting chance which he converted with aplomb. Another excellent goal.
Dons keeper Blessing Oluyemi was harshly booked for handling outside his area on 27 minutes, only the referee and his assistant failing to spot he was clearly inside his area when he picked the ball up. However, the goalie redeemed himself with a fine save from Gilmartin's free kick.
From the resultant corner, Thomson saw his downward header kick up on to the bar before going to safety, another indication this tie was still very much alive.
Then on 38 minutes a penalty for Aberdeen. Towler's excellent pass releasing Bavidge who waltzed round the keeper who felled him before he could score. A booking for Kennedy who was left helpless as Ryan Duncan thundered the spot-kick into the net.
Unfortunately for Alfie Bavidge, Kennedy's challenge forced him off the field with Findlay Marshall taking his place.
A good first half for Aberdeen who were fair value for their lead at the break, but Saints were still very much in the tie.
Half time - St Mirren 1 Aberdeen 3
Seven minutes into the second period Adam Emslie raced clear of the defence and Kennedy tripped him before he reached the penalty area. A straight red was shown to the home number one which meant Gallagher had to be sacrificed to allow Welsh to take over in goal. And his first act was to pick the ball out of his net as Harvey turned in the rebound after Duncan's fierce free kick cannoned off the woodwork. A hat-trick for Liam and a three goal cushion for Aberdeen.
Once again Saints fought back, and, despite their numerical disadvantage, enjoyed a good spell aided by an ever strengthening wind behind them. On 65 minutes Gilmartin reduced the deficit then four minutes later a far post header was knocked off the line.
All of a sudden, the Dons defence looked anxious. Oluyemi saved well from Offord and another last gasp block from Towler kept the home side at bay.
A rare foray up the other end saw Welsh save well to deny Harvey a fourth goal. Substitute Findlay Marshall was unfortunate to see red after a couple of very soft bookings from referee Trayner then another Saints goal from Struthers set up a grandstand finish.
Despite their best efforts though it wasn't to be for St Mirren, so Aberdeen will go into the hat for the quarter-final draw.
Full time - St Mirren 3 Aberdeen 4
Barry Robson: "I thought we were very comfortable first half, and then we get a fourth goal. But we always knew the second half would be so tough with that wind.
"I think it is difficult to actually tell who has played well tonight. I thought we controlled the game in the first half, but second half just becomes a lottery. It was a tight, narrow pitch which does not suit the way we wanted to play but at the end of the day, we got the job done.
"We have created chances all season and maybe not taken as many as we would have liked, which is understandable as the boys have changed physically over the past six months because of the work we have put into them, to make them quicker and stronger but their technique is still trying to catch up. However, Liam took his goals absolutely brilliantly early on.
"The biggest credit I can give the players was that they had to play the conditions and they had to win the fight and they did that.
"We started to get a bit nervous towards the end of the game, and that has been a theme this season. It is down to young players needing to learn to be calm and not getting spooked when things don't go our way. That leads to indecision. This will improve with experience so hopefully we can try settle them down as we move forward.
"If we have everyone fit and available, we are hopeful we can have a good run in this competition but we are still a young side this year compared with a many of the other teams who are a year older and that makes a big difference at this level. We will still give it our very best shot."