The second period was much more in the balance, with former Rover Todd Kane striking a post before Ben Brereton's second of the season broke the deadlock.

Lyndon Dykes levelled from the spot and the R's grew in confidence, but Armstrong's class settled proceedings.

He put Blackburn back in front with a confident finish and then made the points safe deep into stoppage time by beating Dieng at the second attempt for his 11th league goal of a prolific season.

It ended a four-match winless run at Ewood Park as Rovers moved into the top half of the table. And Mowbray highlighted Armstrong's "mature" performance and its impact on the team.

He said: "Adam does (make a difference) as he has done all season. I think Adam has matured and he's only 23.

"He's a boy really, but his explosive pace at the top end of the pitch allows you to play both ways, to not be overly concerned if you're pinned back around the edge of your box because one pass releases pressure to someone like (Harvey) Elliott to play the pass that he can hit just leaving it in the space for the speed and dynamic movement of Armstrong – it's a devastating effect for the team.

"Teams see that and they are aware of it and don't over-commit men forward which allows you to potentially work on trying to keep the ball out of your net, allows you to build the ball up in their half so they find it difficult to get near your goal.

"When teams gamble as they did, you sit and think we're going to score again on the break here because they're pushing for a goal, as we did in this match."

QPR drop two places to 18th after the defeat and have only won once in nine away outings stretching back to last season.

Mark Warburton thought his side should have come away with something in a "typical Championship game".

He said: "I thought first half we were lucky to come in 0-0. We rode our luck, two great saves from Seny and we should have been two down in truth.

"We made two changes at half-time and I thought second half we were much better.

"You go down to a goal from a corner, the ball bounces in your box and that can happen. We then get the penalty back and we were in the ascendency then, on the front foot, and I really fancied us to go on and win the game.

"That was a typical Championship game and the basics. They've scored a second goal from us having great possession on the edge of their box. You lose a duel, then a four-v-two and you pay the price.

"We are a young squad learning, but that is a typical Championship game and we have to get something out of it."