David Hoilett’s clinical late goal put Blackburn through to the FA Cup fourth round after a poor match against weakened Championship pace-setters QPR.
Hoilett who scored with a precise shot from the edge of the area after he had been set up by El-Hadji Diouf.
To make matters worse for QPR, Jamie Mackie suffered a double fracture of his leg after a collision with Gael Givet, who was also carried off.
QPR hit the woodwork twice through Petter Vaagan Moen and Kaspars Gorkss.
Vaagan Moen’s 40-yard free-kick in first half injury-time was tipped on to the bar by Mark Bunn and then Gorkss hit the bar with an 84th minute header, although the west Londoners were always second best.
Blackburn had a string of first half chances but failed to take them.
Marne Biram Diouf and Ryan Nelsen both missed the target before Paddy Kenny denied both Dioufs and Givet.
At the other end, before he was injured Mackie had a shot cleared off the line by Nelsen.
Rovers continued to dominate in the second half and Hoilett finally won it with his first goal for 16 months.
Half-time substitute Jason Roberts then should have made the game safe but headed wide when unmarked from Josh Morris’s cross to the near post.