Martin Rowlands, Patrick Agyemang and Rowan Vine were all on target, as the R's came from behind to send Scunthorpe United spiralling towards League One.
Rangers trailed to Grant McCann's fine free-kick, only for the hosts to respond courtesy of a debatable Rowlands spot-kick.
Agyemang put the R's in front when he smashed home Akos Buzsaky's classy 79th minute through ball, before Vine put the icing on the cake with a well-taken third goal in stoppage time.
Following hot on the heels of Tuesday's 3-2 victory against Blackpool, De Canio named an unchanged starting XI.
Scunthorpe boss Nigel Adkins opted for experienced front-man Geoff Horsfield in attack, which meant former Millwall striker Ben May had to make do with a place amongst the substitutes.
Buoyed by their impressive recent home record, the R's - kicking towards the Loft End - made a positive start.
Agyemang's cross was met by the on-rushing Dexter Blackstock in the fourth minute, but he could only knee the ball into the grasp of Iron custodian Murphy.
But it was Scunthorpe who grabbed a surprise eighth minute lead, when Fitz Hall was harshly penalised for a foul on Horsfield and McCann stepped up to curl a sublime 25-yard free-kick in to the bottom right hand corner.
The R's responded in the only way they know how, peppering the Scunthorpe rearguard with a series of balls into the box.
They were very nearly rewarded in the ninth minute, only for Agyemang's strike to be ruled out for offside, after Murphy failed to hold on to Martin Rowlands' initial deflected effort.
As the R's continued to throw men forward, Murphy came to Scunthorpe's rescue, diving full stretch to his left to tip Agyemang's close range volley wide, after Akos Buzsaky fed the ball in from the right flank.
Damien Delaney was getting forward at every available opportunity and when Buzsaky and Rowan Vine combined to devastating effect, the R's full-back thrashed a left footed drive inches wide of Murphy's left hand upright.
At the other end, Jim Goodwin fired into the side netting, but it was Rangers who continued to pose the greater attacking threat heading into the break.
The inevitable equaliser arrived three minutes before half-time, when Izzy Iriekpen was harshly adjudged to have sent Vine tumbling to ground inside the box and Rowlands stepped up to send Murphy the wrong way from the spot.
Each and every Scunthorpe player bemoaned referee Mr Thorpe's decision, and both Andy Crosby and Murphy were booked for their part in the protests.
The second half took time to catch fire, as Scunthorpe continued to frustrate the R's with their impressive work ethic and dogged determination.
The major talking point of the early exchanges centered around a brief altercation in the 64th minute, which eventually resulted in Hall picking up a yellow card for his involvement.
The R's faithful were made to wait until the 72nd minute mark to see Rangers create a chance, as Mikele Leigertwood fired wide after expertly bringing down Rowlands' neatly disguised pass.
Buzsaky went close soon after with a back post volley, as Scunthorpe became encamped in their own half.
Rangers' continued to knock at the door and in the 79th minute Buzsaky found the key to unlock it.
Picking up possession from Rowlands, the Magical Magyar played a double one-two with Agyemang, which resulted in the latter facing a one-on-one contest with Murphy.
The R's hit-man took one touch to set himself, before firing into the roof of the Scunthorpe net, for his ninth goal in QPR colours - and his 13th of the campaign.
Scunthorpe rallied briefly, but Camp was in the right position to save with his feet, as Matt Sparrow fired a late effort goalwards.
Vine put the seal on the R's comeback when he delicately lofted the ball beyond Murphy, to cap a scintillating second half display from De Canio's men.
QPR: Camp, Delaney, Mancienne, Blackstock, Buzsaky (Mahon 81), Rowlands (Stewart 92), Connolly, Agyemang (Lee 93), Vine, Hall, Leigertwood.
Subs: Pickens, Balanta.
Scorers: Rowlands 42 (pen), Agyemang 79, Vine 94
Bookings: Connolly 55, Hall 64, Leigertwood 80
Scunthorpe United: Murphy, Crosby, Iriekpen, Sparrow, Goodwin, Hayes (Hurst 87), Baraclough, Horsfield, Cork, McCann (May 83), Butler.
Subs: Hobbs, Lillis, Horlock.
Scorers: McCann 8
Bookings: Crosby 42, Murphy 42
Referee: Mr M Thorpe
Attendance: 14, 499
