Rovers striker Yakubu, back from suspension, opened the scoring in the 15th minute with a shot from the edge of the penalty area, Steven Nzonzi extended the lead in the 23rd by converting Junior Hoilett's pass and Nedum Onuoha's own-goal then made it 3-0 just prior to the interval.
Substitute Jamie Mackie netted in the 71st minute and again in the closing stages to set up a nervy finale, but Blackburn held on for the victory, the ideal response to last weekend's humiliating 7-1 defeat at Arsenal.
A two-goal win would have seen Rovers move out of the Premier League relegation zone and send QPR into it, but Mackie's late second strike means the London outfit stay where they are in 16th, while Blackburn are up a place to 18th, with both clubs level on 21 points from 25 games.
Top scorer Yakubu returned to the hosts' starting line-up after serving a three-match ban, but defender Gael Givet was beginning a suspension following his sending-off in the Arsenal game, so Grant Hanley also came into the team, along with Bradley Orr, who was making his first start since joining from the R's on transfer deadline day, and Mauro Formica.
QPR's former Rovers boss Mark Hughes - without suspended frontman Djibril Cisse - made three changes following the 2-1 defeat to Wolves, bringing Fitz Hall, Armand Traore and Akos Buzsaky into the side.
Blackburn were eager to put their debacle at the Emirates Stadium firmly behind them but they almost suffered further embarrassment early on when Hanley made an error and Bobby Zamora looked to capitalise, only to see his cross intercepted.
Rovers soon settled down, with Hoilett firing an effort against Anton Ferdinand, and on the quarter-hour mark they took the lead as Yakubu marked his comeback in style.
The Nigerian collected the ball from Nzonzi's flick-on, turned and smashed home past Paddy Kenny for his 14th goal of the season.
QPR tried to make a quick response as Onuoha headed wide, but soon after Blackburn had doubled their advantage as Hoilett broke into the box and teed up Nzonzi, who swept the ball in.
Hoilett looked to put Rovers further ahead but his shot was blocked.
A tame attempt from QPR's Adel Taarabt did little to trouble Paul Robinson, and Morten Gamst Pedersen then drove a free-kick into the visitors' wall.
Hanley failed in a bid to connect with a corner, the Scot injuring himself in the process although he was able to carry on, before Buzsaky lashed well wide and Robinson got down to save Traore's shot.
Blackburn then made it 3-0 in first-half stoppage time, Scott Dann heading the ball across the area for Hoilett, whose shot went in off Onuoha.
There was a setback for Rovers at the start of the second half with Hoilett having to be withdrawn, Adam Henley the man to come on.
Moments later, though, they almost had another goal as Yakubu sent an audacious chip against the crossbar.
Onuoha found himself through in the 65th minute but produced a poor strike which Robinson saved with ease and Taye Taiwo then cracked one wide for the visitors.
QPR were applying some considerable pressure, and with a little under 20 minutes to go they pulled a goal back as Jamie Mackie - on for Buzsaky - put in Taiwo's cross with a close-range finish.
Mackie was then presented with another opportunity, but shot at Robinson.
The goalkeeper turned an effort from Taarabt around the post and Shaun Wright-Phillips hit one over the bar.
Mackie then struck at the death to make it 3-2, but it too late for the R's to salvage a draw.