Jordan Hugill scored two minutes from time to snatch Preston a 1-0 win against an ill-disciplined QPR at Deepdale.
Jamie Mackie was given a straight red card after 22 minutes but the visitors battled valiantly to keep Preston at bay until Hugill struck late on.
It is now five games without a win for QPR - who also had Alex Baptiste sent off after the final whistle - while Preston made it four games unbeaten in the Sly Bet Championship.
Preston started brightly and Alan Browne had two chances in the fifth minute. First the midfielder broke to the edge of the area and his strike was parried by Alex Smithies, before Browne was picked out by Callum Robinson's cross but headed over from six yards.
The Lilywhites had not scored in their previous two home games but their task was made much easier when QPR were reduced to 10 men midway through the first half, Mackie given a straight red for a crunching tackle on Tom Clarke.
And skipper Clarke, making his first start since April after an Achilles injury, had a chance to give Preston the lead seven minutes later, but headed wide from Paul Gallagher's whipped free-kick.
QPR had an opportunity to take a shock lead after 55 minutes as Ilias Chair, making his league debut, had a shot from 18 yards deflected just wide of the near post.
The home crowd at Deepdale were showing their frustration and Preston responded with a period of sustained pressure, the clearest chance coming on the hour mark when Ben Pearson squared for Robinson who was superbly denied from eight yards by a Baptiste block.
Three minutes later Pearson weaved his way past a couple of challenges on the edge of the area before his shot looped high into the air and was claimed by Smithies.
But the QPR keeper was less convincing after 67 minutes when Gallagher launched an effort from distance that he fumbled behind him and was forced to gather at the second attempt.
Despite being a man light, QPR remained a threat and came close with a set-piece in the 75th minute, as Chair's delivery evaded everyone and almost crept into the far corner.
Preston, who had not lost to QPR at Deepdale since 1980, pushed to make their advantage count and Gallagher came close in the 83rd minutes only to sweep a shot wide from 18 yards.
But two minutes from time they finally got the breakthrough as Hugill was sent through one-on-one and slid the ball under Smithies to snatch the win.
And there was still time for Baptiste to get shown two yellow cards - the second after the final whistle - as QPR's poor away form continued.