Bojan Miovski's dramatic penalty in the 10th minute of stoppage time denied brilliant St Mirren a third win from three Scottish Premiership games as disjointed Aberdeen snatched an unlikely point in Paisley.
Heading two points clear at the top of the table, St Mirren were left utterly stunned when Miovski rolled in from the spot following Alex Gogic's late handball.
Having somehow trailed at half-time when Jonny Hayes' crossed free-kick deceived goalkeeper Zach Hemming, Stephen Robinson's side re-asserted their dominance after the beak and finally got the rewards their play deserved.
Greg Kiltie levelled with a penalty just before the hour mark after Angus MacDonald was penalised for handball. Mikael Mandron played in fellow substitute Alex Greive to score what looked like being the winning goal with 14 minutes left.
By that point St Mirren had already had goals from Keanu Baccus and Kiltie ruled out for offside, and also forced Kelle Roos into several good saves as they ran all over and bullied a frantic and shaken Aberdeen.
But the visitors were given a scarcely-deserved lifeline when Gogic blocked Leighton Clarkson's shot with his arm.
And even after Miovski appeared to score from the spot, the drama was not done. The Macedonian slipped as he struck the ball, appearing to hit it back off himself and into the net.
But despite a background Video Assistant Referee (VAR) check the goal stood, leaving St Mirren devastated at being denied what seemed an inevitable victory.
"I don't know, I'm miles away from it," Robinson responded when asked about the incident.
"I think, if that dominates the headlines and the talk, I think it's an injustice to the play and quality we put on show today.
"We didn't have the luck of the decisions today. We had two goals disallowed and a penalty given by VAR, at both ends to be fair. But we feel aggrieved not to have three points that our play and performance merited.
"But all you can do is keep doing that. I'm delighted with this group of boys. They give everything and play with a lot of quality they don't maybe get credit for."
Player of the match - Greg Kiltie
St Mirren left baffled, Aberdeen abysmal - analysis
St Mirren will play much, much worse than they did here and win games this season. Robinson will be baffled at how his side did not make history by becoming the first St Mirren team to win their first three top-flight games in 75 years.
As usual they were organised and intense, with plenty of quality in the wing-back and forward areas with Ryan Strain, Kiltie, and Conor McMenamin all outstanding again.
It was incredible they found themselves down at the break, but that did not make it inevitable they would go and get themselves in a position to win the game. Their attitude to continue despite the early sucker-punch was admirable.
Having victory snatched from them will hurt, but they have been excellent this season.
As for Aberdeen, this was the worst they have looked under Barry Robson. They started the game by constantly looking for the long ball, despite lacking a target man up front, but then when they tried to play the passing was loose.
The defence of MacDonald, Slobodan Rubezic, and Jack MacKenzie was unfamiliar and played like it. St Mirren ran amok.
Yes, they have a massive second leg against Swedish champions Hacken to come on Thursday for a place in the Europa League group stage but, given they are guaranteed to have European football to Christmas regardless, they need to get to grips with three games a week.
Lots of new signings mean inevitable teething problems, but Aberdeen are winless in the league and cannot afford to keep dropping points.
What they said
St Mirren manager Stephen Robinson: "Let's give the players credit - they were outstanding. The style of football, the way we played and have been all season, we dominated from start to finish.
"We should've taken three points from it. Sometimes you need a bit of luck - we didn't have that, especially at the end. But the character and quality of the players, against a very good Aberdeen side, we made them look average today."
Aberdeen manager Barry Robson: "I thought we were probably a yard off it all over the pitch. What I told the players is that it is a learning curve - that's what happens when you play a high pressing game against Hacken and then play the form team in Scotland on a Sunday.
"We never really got going at any stage. What I am pleased with is the way they hung in and fought and the spirit between them all."
St Mirren are away to Livingston in the Premiership next Saturday before the international break (15:00 BST), while Aberdeen host Hibernian on Sunday (15:00) after the second leg with Hacken at Pittodrie on Thursday (19:45).