"Our performance was not good enough to win this kind of game," Wenger said. "QPR had a little bit of extra special commitment.
"Overall we can only congratulate QPR for their attitude and be unhappy with our own performance. What we produced on the day was not good enough.
"Subconsciously something was missing today. In the Premier League if you miss something on the commitment front you are beaten. That is what happened today."
Asked if complacency had been a factor, Wenger added: "It is difficult to single out one reason, but why not?
"We played against a team who play for survival. We prepared properly but we missed something today and you could see that."