Harry Redknapp's team may now have to settle for the play-offs following successive losses and there is a possibility they could meet Gary Bowyer's men there after they extended their unbeaten run to seven games, with sixth-placed Reading now just four points ahead.
Rudy Gestede fired home a brilliant first eight minutes in before Rangers goalkeeper Rob Green, whose England career is best remembered for his calamitous error in the 2010 World Cup against the USA, allowed Tommy Spurr's shot to creep past him early in the second period.
The team-sheet saw both managers name a Keane twin in their starting line-ups, Blackburn's Michael coming up against Rangers' Will for the first time in their careers.
And it was the latter, marginally the younger of the two Manchester United loanees, who looked like making an early impact when he twice ran behind the hosts' defence.
On the first occasion Rovers captain Grant Hanley atoned for an error to rob him in the area while, moments later, referee James Adcock adjudged the QPR forward had lifted his leg too high in scooping over goalkeeper Paul Robinson.
That decision looked harsh and it proved pivotal when Gestede broke the deadlock. The former Cardiff forward collected Tom Cairney's pass and took one touch before drilling a 25-yard bullet beyond Green in the Rangers net.
It was Gestede's seventh goal since moving to Ewood Park and he was proving a real handful, flicking a header on which Jordan Rhodes could only prod into Green's gloves.
While the Keane twins were currently flying the flag for Manchester United it was Ravel Morrison, another to ply his trade at Old Trafford, who nearly produced an emphatic leveller.
The visitors worked a short corner into the England Under-21 international and, on the full, he smashed a volley from the edge of the area into Robinson's fists.
Redknapp's side looked vulnerable in the air, though, and both Hanley and Gestede would head wide before the half was out.
At that point it looked like Benoit Assou-Ekotto's comedic foul throw, where he changed his mind at the last minute, would go down as the evening's biggest gaffe.
Yet Green's howler three minutes into the second period proved far more costly. Full-back Spurr edged into the area and fired a hopeful shot at Green's near post and the former England international somehow allowed the ball to creep between his body and the woodwork.
Gary Bowyer's men were flying, Rhodes almost moving into a shooting chance before Craig Conway's curling effort brought a routine stop out of Green, as the home crowd cheered each pass. However, Will Keane almost silenced them as his placed effort came back off a post.
Redknapp threw on strikers Modibo Maiga and Charlie Austin, whose Burnley ties have not been forgotten at Turf Moor, but Blackburn looked dangerous on the break as Jason Lowe's deflected effort went wide before substitute Luke Varney steered another attempt inches beyond the far post.
There was to be no way back for the visitors and Rovers' victory was likely to be greeted with delirium from both their own fans and their biggest rivals.