Another pitiful home performance saw Aberdeen drift back into the relegation dogfight as they were beaten by a resolute Partick Thistle side who deservedly took all three points thanks to an early Alex Burns goal.
Any hope Aberdeen had of making the top six has now gone. As for Thistle this was their third win against the Dons this season.
Partick were well worth the win with both Scott Paterson and Burns outstanding.
Thistle shocked the Dons in the 12th minute when a throw-in for the hosts was won in the air by David Lilley.
He headed the ball on to Gerard Britton whose flick took Burns beyond the Dons defence from where the diminutive striker strode unopposed into the area to score his 14th of the season from eight yards out.
In the 17th minute the Dons should have been on level terms when Russell Anderson rose unchallenged to head James McAllister’s corner over the bar.
A long ball out of defence from Alan Archibald saw Britton out-muscle Phil McGuire before the Dons defender blocked his effort at the expense of a corner.
Back came the Dons in the 21st minute when Kevin Rutkiewicz’s first-time effort from Steven Tosh's lay-off skimmed the bar on the way over.
In the 34th minute a quick break by Kevin McNaughton and Tosh saw the latter drive at the Thistle rearguard before finding Leon Mike who was unceremoniously brought down by Archibald for a penalty.
Before the kick could be taken Archibald was yellow carded for the poor challenge and subsequent dissent.
McGuire was handed the task of taking the kick but his low weak effort was easily beaten away by Kenny Arthur to maintain the visitors’ advantage.
An error in midfield by Paul Sheerin allowed Britton to advance to the edge of the Dons area, but as he was being closed down by Anderson his low effort was comfortably held by David Preece.
The Dons made a double substitution in the 64th minute in an effort to change the course of the game - Rutkiewicz and Darren Mackie were withdrawn and replaced by Ross O'Donoghue and home debutant Leigh Hinds.
Thistle at this stage were quite content to get men behind the ball and contain Aberdeen whose midfield made little impression on the game.
The visitors almost scored a second when Preece had to be lively to touch a Derek Fleming free kick round the post at full stretch.
Back came the Dons at the other end when a smart turn and shot from the edge of the area by Hinds tested Arthur in the Thistle goal.
There was some controversy with three minutes left when McAllister stupidly earned his second yellow card for arguing with referee Dougal over a throw-in decision which resulted in the Dons seeing out the remainder of the game with just ten men.