Airdrie's hopes of a third-placed League One finish are hanging by a thread, going into the last game of the season at Edinburgh next Saturday, after they fell to a first defeat in eight games.
Clinical Queen of the South despatched them with two goals inside two first-half minutes and a stunning free kick with eight minutes left.
It's now only goal-difference separating Airdrie from Alloa Athletic, who as things stand will face either Championship second-bottom side Cove Rangers or Hamilton Accies in their play-off semi-final.
The Diamonds, who pulled a consolation goal back through sub Salim Kouider-Aissa with 20 minutes left, will face Scottish Cup semi-finalists Falkirk if they hold on to third place.
Former Hearts star Harry Cochrane had Queen of the South ahead 20 minutes in, and they doubled that lead two minutes later through ex-Albion Rovers defender Euan East.
Airdrie made changes at the interval and second half, and Kouider-Aissa headed in Charlie Telfer's cross to halve the deficit.
But Paton sent an unstoppable shot into the roof of the net to seal the win in 83 minutes.
Airdrie weren't at their best in the first half, but weren't miles behind Queen's either, who were clinical with their chances as Lewis Gibson in particular caused them problems with his deliveries.
The second half was much the same, as Airdrie tried to get themselves into the game but didn't really test Botterill, while Queens, in control of the game, were content to hit on the counter-attack.
Airdrie did pull the goal back, and threw on Gabby McGill with 12 minutes left, but even he couldn't rescue a point.
Airdrie boss Rhys McCabe made three changes from the side that drew against leaders Dunfermline here last week. Ben Stanway, Euan Deveney and Lachlan Byrd replaced Cammy Ballantyne, Dean McMaster and Adam Frizzell, all of whom were on the bench.
His Queen of the South counterpart Marvin Bartley made four changes from the line-up that lost 3-2 against Montrose. Goalkeeper Gordon Botterill replaced Kevin Dabrowski, while Lewis Gibson and Ciaran McKenna came in for suspended duo Jack Brydon and Stephen Hendrie, and Harry Cochrane slotted in for Lee Connelly.
The first chance of the game came for Airdrie in the first minute when Justin Devenny's cross from the right was headed just over the far post top corner by McCabe.
Callum Smith went on a run down the left and his cross/shot was deflected narrowly wide of the left post in 12 minutes.
Queen of the South's Ruari Paton stung Josh Rae's palms with a fierce shot two minutes later, but it was pushed away from the right corner.
Lewis Gibson raced down the left and picked out Josh Todd in 16 minutes, but his effort was blocked by Rae at the left post.
Airdrie went close again in 18 minutes when Euan Deveney's cross from the left was headed over by Smith.
But Queens took the lead in 20 minutes when Gibson's cross from the left was headed across Rae and into the left corner by Cochrane.
And they doubled that lead two minutes later when Gibson's corner from the right was bundled in by East.
Charlie Telfer sent a shot fizzing across goal from the left corner of the box in 42 minutes, but Airdrie still couldn't get their way back into the game.
Ruari Paton nearly put Queens 3-0 ahead in 47 minutes, but Rae made a good save to deny him.
Cammy Logan went close for Queens in 54 minutes as he ended a promising move by sliding in at the left post, but keeper Rae diverted it past.
Calum Gallagher sent Devenny down the right wing and his cross was eventually blasted over by sub Dean McMaster, as Airdrie tried to get into the game.
But the Diamonds pulled a goal back in 70 minutes when sub Kouider-Aissa headed in a Telfer cross.
However, Queens made sure the three points were travelling back to Dumfries with them as Paton sent an unstoppable free kick into the roof of the net in 83 minutes.
AIRDRIE: Rae, Watson, Byrd, Fordyce, Deveney, Stanway, Devenny (McGill, 78), McCabe (McMaster, 46), Telfer, Gallagher (Kouider-Aissa, 58), Smith.
Subs (not used): Hutton (GK), Ballantyre, Taylor-Sinclair, Frizzell, Dixon, McGill.
QUEEN OF THE SOUTH: Botterill, Gibson (Muir, 71), P. McKay (D. McKay, 53), East, Logan, Cochrane, Wilson (Murray, 56), Todd, McKenna, Paton, McKechnie (Connelly, 71).
Subs (not used): Dabrowski (GK), Morrison, McGrory, Irving, McMahon.
Booked: Botterill (79)
Referee: Grant Irvine.
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