ROTHERHAM failed to make their first-half dominance count as two goals soon after the interval gave Jimmy Floyd Hasselbaink his first win as QPR manager at the ninth attempt.
The former Burton Albion chief and Dutch international striker was indebted to strikes from Junior Hoilett and Matt Phillips for getting off the mark - Sebastian Polter tapping home the third in stoppage time.
Having ended the unbeaten away record of Brighton in midweek, Neil Redfearn selected an unchanged Millers side as they went for a fourth straight home win.
It meant a 4-4-2 formation with Danny Ward again partnered up front by fellow midweek scorer Matt Derbyshire.
QPR went 4-4-1-1 with Hoilett playing behind striker Polter.
Goalkeeper Alex Smithies returned for QPR from elbow trouble, former England goalkeeper Rob Green left out due to contractual problems and a proposed move to Bournemouth.
The visitors also sold striker Charlie Austin in the morning for around £4m - a fee far less than they could have commanded in the summer after being relegated from the Premier League.
Smithies made a couple of smart saves as Rotherham forced five corners in the opening eight minutes.
They almost went ahead in the 29th minute when Paul Green cut inside from the right and curled his shot against the far post, Nedum Onuoha sliding in to prevent Derbyshire tapping home the rebound.
QPR rarely threatened but Lee Camp did well to block a far post downward header by Grant Hall from a free-kick before the danger was cleared.
Danny Ward also headed narrowly wide before the half ended goalless.
QPR struck seven minutes after the break when Hoilett burst down the left channel and stayed on his feet to poke the ball past Camp under Paul Green’s sliding challenge.
It got worse for the Millers two minutes later as Massimo Luongo fed Phillips, who fired the ball home after Kirk Broadfoot slipped in making his challenge in the area.
Jonson Clarke-Harris immediately replaced a hobbling Danny Ward to partner Derbyshire, who was later replaced by Emmanuel Ledesma.
The Millers built late pressure, forcing three corners in succession but their efforts proved to no avail.
QPR always looked dangerous on the break and Fer set up Polter to make it 3-0 with both players looking offside.
While it was Rangers’ first win since early December, it was also Rotherham’s first defeat at home since then and Neil Redfearn was left scratching his head at the severity of the loss.
The Millers created enough chances to be two or three goals to the good at the interval, with Paul Green being denied by a post and Matt Derbyshire missing an open goal from the rebound.
“It was probably one of the weirdest 3-0 defeats I have ever been involved in,” the Millers boss said. “Had it been 3-0 to us at half-time that would have been about right.
“The pressure and play we had around the box, but it just shows you the ruthless nature of this division. If you don’t get your noses in front or make hay while the sun is shining, then you are open to that sort of thing.”