QPR manager Steve McClaren was left “shocked and angry” after seeing his side thrashed 7-1 at West Brom.
Rangers are propping up the table after losing all three of their Sky Bet Championship games so far this season.
Former England boss McClaren said: “After 50 minutes I thought we were fine but we made two mistakes and we collapsed.
"That is unacceptable to QPR fans, unacceptable to us, the players, the club and we have to do something about it on Tuesday (against Bristol City).
"We need a reaction. In the first three games of the season we fought. I never saw that coming and I am shocked and angry.
"We knew that this was a young squad, talented, but talent doesn’t get you everywhere. This was a harsh lesson and we will see who comes out of that.
"There is a lot of things going on behind the scenes – embargoes, fines and we can’t do this and we can’t do that – but we are working every day with the loan market open.
"We need reinforcements to help these younger players. After the third goal we couldn’t cope and that is to do with mentality. We need to go through the fire to come out the other end and this is the fire.
"Today I didn’t like what I saw and we have to do something about it and make sure it doesn’t happen again. Let’s see how they react after being hurt."