QPR won the game with a late Clint Hill goal as they kept their unbeaten start to the season whilst bringing an end to the home side's same record.
McDermott pointed out his side's poor attacking display as a factor behind the defeat.
He said: "It was a tough game, we knew that, we knew what we were coming up against. They worked hard, it was a good away performance.
"We thought we deserved a point; did we do enough to win it? Probably not.
"They didn't really have too many chances but they scored from a set-play which was poor to say the least.
"You have to take the game to teams at Elland Road. Did we take the game to QPR enough today? The answer is probably no. That's something we've got to work on."
However, McDermott will not let the defeat get to his team as he looks to make amends after the international break.
He added: "We're trying to evolve, we're a new team, we're working together and we'll get there
"It is what it is; we can't affect what's just gone on. Our philosophy doesn't change if we win, lose or draw. We go into the next game looking forward to it."