On an unbelievably drama laden night, Dundee United failed in their bid to reach the final of the Youth Cup after a marathon tie which lasted over four hours due to a fire alert in the Jerry Kerr Stand.
With United leading 4-2 with just over a quarter of the game remaining, it looked all over, but the visitors came back from the dead to leave United crest-fallen and finish with nine men.
United couldn't have got off to a better start with a great goal from Ryan Gauld after eight minutes, steering the ball home from ten yards after his intelligent run onto Jordan Moore's through ball.
Five minutes later Robert Thomson almost made it two, hitting the post after latching on to a misdirected back header.
But the Dumfries side were level after 21 minutes when Paddy flatterly scored direct from a corner.
Ten minutes later Gauld regained the lead with an even better strike than his first.
Taking the ball back to goal he turned to fire the ball high into the top left hand corner.
Bang on the break, Ryan Ferguson went close to extending United's lead when his effort hit the top of the bar.
Due to the fire alert, the second half resumed after almost an hour, but the Doonhamers wasted little time in restoring parity, Lewis Todd rattling in a 25-yarder after 49 minutues.
Their joy was short-lived though because two minutes later, Thomson showed great composure when keeping his cool to net after latching on to a through ball.
Not that the visitors took it lying down, Dean Smith missing the target following good work by the ever dangerous Liam Park.
But a further quality goal from Thomson midway through the second half when he cut in from the right to fire a shot into the far corner for United's fourth looked like booking a Hampden date.
But the stubborn visitors got a foothold back in the game with eight minutes left when Slatterly was allowed to stride forward before unleashing a shot high into the net from 25 yards.
Three minutes later came the turning point in the tie.
Park was hauled down by Craig Bell in the box and after the home defender was red-carded, Dumfries skipper Scott Hooper blasted home the penalty to take the tie into extra time.
And Queens' comeback was completed a minute before the end of the first period of extra time with Gavin Reilly sweeping home a cutback from Robbie Vallance.
Still the incident wasn't over because United were reduced to nine men when John Soutar was shown yellow for a seond time and nine-man United would have taken it to penalties had Jim Atkinson not blocked Jordan Moore's effort when he was clean through on goal.
Dundee United: McCallum, Soutar, Lundie, Smith, Barrett, Johnston, Gauld (Allan 90),Ferguson, Thomson (Hay 78), Moore, Bell. Subs not used: Easton, Lunday, Spark.
Queen of the South: J Atkinson, S Atkinson, Neil (Simpson 103), Wilkinson, Hooper, Handling (Vallance 69), Todd, Park, Reilly, Smith. Subs not used: Drysdale, Young, Hetherington.
Referee: Ross McIntyre.