Paul Hart admitted that his side's inability to take their chances in the first half against Ipswich Town played a large part in their defeat at Portman Road.
The Tractor Boys scored as early as the fourth minute thanks to Jon Walters, though Rangers had a handful of chances to level the match after the opening goal of the game.
But the R's were made to pay after half-time, as Jon Stead stole the show with a double to give Roy Keane's men victory in Suffolk.
QPR manager Hart told www.qpr.co.uk: "I felt the first half performance warranted a better return than we got. We were even unfortunate for the first goal, which took a deflection to loop over the keeper.
"But after that I felt we should have had a penalty and (Adel) Taarabt should have scored from a great cross, he was in front of goal.
"We thought if we could replicate the performance in the first half, we could get a draw. We felt that (we could have gone into half-time leading), I think we lost our legs a little bit."
The Rangers boss also added that his side must improve defensively in the weeks to come, as QPR travel to Sheffield United in third round of the FA Cup on Sunday before playing Plymouth Argyle at home in the league six days later.
"It's hard to swallow, the goals that are going in at the moment are not great goals - we're the architects of our own downfall," explained Hart.
"As you all know, goals change games."
