The Latics had an extra man for around 70 minutes of the Loftus Road clash but only managed to nick a point in injury-time when Shaun Maloney's 20-yard free-kick cancelled out Loic Remy's 85th minute go-ahead goal.
Martinez believes that Wigan were put off by the sending off of R's striker Zamora as it placed more pressure on them to win the match.
"I don't think in the position we are in we can go to places and try and get a draw," he said.
"But the draw at the end is a very good result for us. The sending off affected us more than anything because all of a sudden you feel the responsibility of winning a football game.
"The players took it too seriously and didn't enjoy their football at all, they were pedestrian. We got cagey and forced the play and getting on the ball and playing was a tough job today.
"The sending off was something that should have been an advantage but it ended up being a disadvantage because all of a sudden QPR became well organised and the crowd got behind them."