The Czech Republic international made the most of an error from opposition keeper Alex Smithies to blast home the only goal of the game 20 minutes from time, moving the Rams to within six points of the playoffs.
It also marks a first victory for Gary Rowett in his maiden home game in charge, while QPR's recent resurgence following five wins in their previous seven appears to have come to a halt.
Derby striker David Nugent sent one shot wide and another on target for Smithies to keep out as half time approached, with nothing to separate the sides at the midway point.
Neither side could truly get going after the restart, but it was County - with one win in 10 prior to today - who made the key breakthrough 70 minutes in thanks to Vydra's quick reactions.
Ince saw his shot parried by Smithies and his teammate was there to lash home into the roof of the net from close range - his first attempt of the evening and ultimately enough to settle the contest.
QPR rallied late on and perhaps should have taken a point back to the capital, with Matt Smith failing to beat Carson and Idrissa Sylla's free header hitting the wrong side of the post before going out of play.
There was to be no late drama at Pride Park in the end, however, as Derby held on to ensure that they are just about in the mix for a top-six finish under new boss Rowett.