Kevin Bond suggested QPR’s players lacked fighting spirit after Richard Dunne was sent off during the 3-0 defeat at Sheffield Wednesday.
Dunne was red-carded for the foul that led to Wednesday’s first goal and after going behind Rangers meekly slumped to their fifth defeat in eight matches.
And assistant boss Bond said: “The issue is what has happened after we went down to 10 men and we have spoken about it in the dressing room.
“It is a problem and we have spoken about it. There was a sense of inevitably about how the game was going to go.
“It wasn’t the reaction we were looking for. We are all as a group hugely disappointed with what went on after the red card.”
The result left Rangers 10 points behind second-placed Burnley and looking all but out of the race for automatic promotion.
“It would be lovely to get promoted automatically but I accept it’s a tall order,” Bond added.