The R's were brilliant all over the park as they out-battled the Gunners with first Premier League goals from Taarabt and Diakite.
First Premier League goals for Adel Taarabt and Samba Diakite on either side of a Theo Walcott tap-in were enough for QPR.
And with QPR having arguably the hardest of the run-in’s amongst the bottom sides, this win against a team in the top four will have given the club a tremendous push in the right direction.
Djibril Cisse missed out after receiving his second red card since joining the R’s in January during last week’s game against Sunderland but captain Joey Barton did make a return after being dropped to the bench for the aforementioned fixture after a run of poor form.
Mikel Arteta made his 200th Premier League appearance, while Laurent Koscielny returned to the center of defense alongside Thomas Vermaelen as Robin van Persie looked to add to his already huge goal tally this season.
The hosts started the stronger of the two but Arsenal had the first chance of the game when van Persie's free kick was held at the second attempt by Paddy Kenny after Walcott was scythed down from behind by Clint Hill.
Mark Hughes’ men were cheered on from the whistle from their fans who greeted every free kick won around the area with relish as they look to beat relegation.
Arsene Wenger’s men were struggling to get into this one early doors and were being hounded far up in their own half by the likes of Shaun Derry and Zamora.
But it was free-kick maestro Taarabt who opened the scoring on 22 minutes after a fine through ball by Hill found the Moroccan, he dropped his shoulder, turning Vermaelen inside out, before rifling home past Szczesny
The visitors equalized with their first real attack of the game after 37 minutes and it was completely against the run of play.
Aaron Ramsey and van Persie both went close just before the break as the tide slowly changed following the equalizer.
And it was the away side which continued to pose a threat at the start of the second half without giving Kenny much to do but the Dutch international would keep him busy twice just before the hour mark.
Another free kick was punched away by the Irish international from the Premier League leading goalscorer before he second guessed what van Persie was going to do when put one-on-one with the goalkeeper from Alex Song.
A terrific save around the post kept his side in the game and Taarabt had a shot from range well held by Szczesny.
And that gave QPR its impetus back, and the lead, hugely down to Mackie’s persistence and slightly due to Vermaelen being at fault again.
The ever-energetic striker worked his socks off all game and had the beating of Vermaelen, who slipped over allowing him the space to cut back into the box for Diakite to clinically dispatch past a stranded Szczesny after 66 minutes.
And Barton almost went from zero to hero with a brilliant shot but an even better save from Szczesny kept his side in the game.
Arsenal had a late, late chance with yet another van Persie free kick but he only found the wall as QPR held on in four added minutes for three massive points.