Junior Hoilett’s goal deep into first-half injury time has given visitors QPR a 1-0 lead over the Blues at the break.
Mick McCarthy named an unchanged team for the sixth successive match, while Luke Hyam was on the Blues bench for the first time this season having been recalled from his loan spell at Rotherham.
The visitors, who were without injured star striker Charlie Austin, included former Town man Jay Emmanuel-Thomas and ex-Blues loanee Massimo Luongo on the bench.
Town were first to threaten in the fifth minute, Ainsley Maitland-Niles feeding the overlapping Luke Chambers to his right and the Blues’ skipper sending over a low cross which QPR centre-half Grant Hall inadvertently diverted to his keeper Rob Green from the edge of the six-yard box.
Four minutes later, Daryl Murphy out-battled Gabriele Angella from a Jonas Knudsen long ball down the left but the Irish international striker’s shot flew across the face of goal.
The Blues continued to make most of the early running, winning a couple of corners which came to nothing, before Maitland-Niles just over-hit a through ball for Freddie Sears, then on 15 Murphy saw a shot deflect away from goal off Karl Henry.
There was a scare for Town on 17 when QPR’s lone striker Sebastian Polter escaped behind the backline but lost his footing as he sought to turn inside Christophe Berra as the Blues defender chased back. Referee Darren Drysdale showed no interest in penalty appeals which mainly came from the crowd.
The Scotland international was caught in possession by Hoilett before he could clear but the Canadian international took the ball out of play.
Alejandro Faurlin forced Dean Gerken into his first save of the afternoon on 19, the Argentinian midfielder curling a freekick from 25 yards towards the keeper’s top left but the ex-Colchester man claimed.
Five minutes later, Berra required treatment after a clash of heads from a corner but was OK to carry on, albeit while sporting a bandage.
Town weren’t too far away from the game’s opening goal in the 38th minute when Sears’s cross from the left reached Murphy, whose shot was blocked. The ball ricocheted to the one-time West Ham trainee, whose subsequent effort was diverted over the bar by Hall.
As half moved into injury time Chambers went close, nodding Maitland-Niles’s corner from the left wide at the far post with keeper Green nowhere. The Blues captain clearly thought he should have scored.
The half, which had never really burst into life, seemed set to end goalless until the fifth minute of injury time when Leroy Fer whipped over a cross from the right and Hoilett got in front of Chambers to head past Gerken from a couple of yards at the near post.
There was no time for Town to hit back before referee Drysdale blew his half-time whistle.
The Blues had had the better of a not overly enthralling half until conceding the late goal - another Town will feel they ought to have defended - however, without QPR keeper Green having been forced to make any serious saves. Until the goal, Gerken had similarly been under-employed, aside from Faurlin’s freekick.
Town: Gerken, Chambers (c), Smith, Berra, Knudsen, Skuse, Douglas, Maitland-Niles, Sears, Murphy, Pitman. Subs: Bialkowski, Malarczyk, Hyam, Bru, Oar, Fraser, Varney.
QPR: Green, Onuoha (c), Angella, Hall, Konchesky, Henry, Faurlin, Hoilett, Phillips, Fer, Polter. Subs: Smithies, Hill, Chery, Emmanuel-Thomas, Luongo, Tozser, Sandro. Referee: Darren Drysdale (Lincolnshire).