Chris Ramsey insisted a wrong decision by referee Carl Boyeson cost QPR a point at Birmingham.
Paul Caddis scored the home side’s winner from the penalty spot after Nedum Onuoha was adjudged to have fouled Clayton Donaldson.
The result did nothing to ease the pressure on head coach Ramsey, who argued that the spot-kick should not have been awarded.
“After seeing the penalty incident, the referee has probably cost us the points,” he said.
“Honours-even would probably have been a good result and a good away point for us, but it wasn’t to be.
“Both teams didn’t create many clear-cut chances. In the end it went down to the referee’s dubious decision.”
However, Ramsey admitted the poor defending that has marred Rangers’ season so far was evident again when Paul Robinson headed in an equaliser after Matt Phillips had put QPR ahead.
He said: “Obviously we didn’t defend that correctly and we gave away a silly free-kick again, which has happened to us a few times this season. Then we’ve been punished for not concentrating.”