Idrissa Sylla’s goal on the half hour has given QPR a flattering 1-0 half-time lead over the Blues at Loftus Road.
Josh Emmanuel replaced Grant Ward in an otherwise unchanged Town XI, which lined-up in a 3-5-2 formation.
Emmanuel started at right wing-back with Myles Kenlock at left wing-back with skipper Luke Chambers, Adam Webster and Christophe Berra the three centre-halves.
Cole Skuse, Kevin Bru and Tom Lawrence were in central midfield with Brett Pitman again partnering David McGoldrick up front.
QPR made two changes with Jordan Cousins and Ariel Borysiuk taking over from Sandro and Yeni Ngbakoto in midfield. Irish youngster Ryan Manning, who trained with the Town academy as a schoolboy, made his senior home debut.
The game started frantically but with neither side being able to create an opening. QPR wideman Jamie Mackie was probably fortunate not to pick up an early yellow card for a late challenge on Webster, who was playing in the centre of the Town defensive three.
In the 10th minute Pitman took a nasty kick in the face from Ariel Borysiuk on halfway but was OK to carry on after treatment. Referee Tony Harrington had waved play on with Lawrence breaking into the final third but the on-loan Leicester man was crowded out, although believing he had been fouled.
Town, in their Barcelona-style third kit, threatened for the first time in the 13th minute when Lawrence sent in an under-hit freekick from the left and McGoldrick’s header looped over the bar.
But the Blues were getting on top and were having most of the ball. On 14 QPR keeper Smithies was forced off out of his goal to his left to paw away a Pitman flick intended for Bru.
Then, from the resultant corner, the ex-Huddersfield man did well to get down to his left to save McGoldrick’s well-struck shot from a tight angle on the right.
On 17 Lawrence played Emmanuel in on the right of the box, the youngster crossing towards Pitman from the byline but a defender blocked.
The game switched to the other end with QPR winning a series of corners but without turning them into a significant chance.
McGoldrick threatened again in the 27th minute after Skuse cut out a QPR attack on the edge of the Town box and sent the Irish international striker away. The Blues number 10 tricked his way past Joel Lynch before hitting a shot which the former Huddersfield man managed to get back to block. A subsequent cross similarly found Lynch in its path.
But despite the Blues having had the better of the game’s few chances, the home side took the lead on the half hour.
Berra misjudged a James Perch long throw from the right, his header looping into the box behind him, and escaped Webster to powerfully volley past Bialkowski from close range as the ball came over his shoulder.
From Sylla’s perspective it was a fantastic strike but from Town’s it was a goal which shouldn’t have been conceded.
Soon after the goal Sylla underwent treatment for a head injury and was eventually replaced by summer Town target Conor Washington.
Deep in four minutes of injury time largely as a result of the Sylla injury, the Blues won a freekick on the left midway inside the QPR half. Lawrence’s initial ball into the box was returned to him and his subsequent cross found Chambers at the far post from where the skipper smashed a shot high and wide from a tight angle when he ought to have sent a low ball across the area.
The Blues hadn’t deserved to be behind at the break having had the better of the half overall, keeping the ball and moving it around confidently at times, and having created most of the period’s few opportunities.
The change of system had allowed Emmanuel and Kenlock to get forward on either flank, while the back three had been largely comfortable.
But Smithies had only really been tested by McGoldrick’s effort at his near post. At the other end Sylla’s goal - which was brilliantly taken but as so often recently came as a result of a series of Town errors - had been the only QPR chance of note.
QPR: Smithies, Bidwell, Hall, Lynch, Borysiuk, Cousins, Mackie, Wszolek, Perch, Sylla (Washington 38), Manning. Subs: Ingram, Onuoha, El Khayati, Ngbakoto, Shodipo, Sandro.
Town: Bialkowski, Emmanuel, Kenlock, Chambers (c), Webster, Berra, Skuse, Bru, Lawrence, Pitman, McGoldrick. Subs: Gerken, Knudsen, Douglas, Dozzell, Ward, Sears, Varney. Referee: Tony Harrington (Cleveland).