Derby County are 45 minutes away from missing out on a place in the Championship's playoff places after Reading took a 1-0 lead in at half time at the iPro Stadium.
On-loan Kwesi Appiah gave the visitors a perfect start when he broke clear of the Derby defence before calmly slotting home inside the first two minutes for his first Reading goal.
Raul Albentosa was appealing for a penalty when his shot struck the hand of a Reading defender, but the referee waved away the optimistic appeals.
Tom Ince went close for the Rams on 11 minutes when his curled effort was saved before Richard Keogh flashed a header wide.
Derby were almost level when Ince picked out Johnny Russell at the far post, but the latter couldn't find the target from close range before the half-hour mark.
Appiah almost claimed his second of the afternoon 10 minutes before the break when he headed Jem Karacan's effort just wide.
Lee Grant did well to thwart Oliver Norwood's free kick shortly before the break as the Royals pressed for the second goal that would leave Derby with an uphill task in the second half.
Darren Bent had a glorious chance to level in stoppage time when Russell was fouled inside the area, but the recalled striker saw his penalty saved by Adam Federici.
