Kevin Bond admitted QPR paid the price for a shoddy defensive lapse in their 1-0 defeat at Charlton.
Johnnie Jackson pounced at the far post to score in injury time and condemn the visitors to a third consecutive loss.
Rangers assistant boss Bond said: “We’ve found goals hard to come by this season. In the early part of the season we dominated in terms of possession, without the end product.
“Today I thought we got back to that and at least passed the ball against a team that are fighting for their lives. We were aware it was going to be a difficult game.
“The difference is that before we weren’t shipping goals. Today the worst came to the worst. We fell asleep for half a split-second and it’s cost us the game.
“We need to get back to being difficult to beat and if that means winning by the odd goal, that’s what we’ve got to do.”
Rangers expect Niko Kranjcar, who missed the match with a hamstring problem, to be fit for next Saturday’s game against Leeds.