The Royals took the lead through Nathan Baker's own goal, but Christian Benteke pulled the visitors level within a minute before Gabriel Agbonlahor gave Paul Lambert's men a much-needed win just before the break.
McDermott's men are now level on points with QPR but the 51-year-old insisted they can still stay up despite an unkind run of fixtures, citing their rivals as an example of what a couple of positive results can do.
When asked by reporters whether he thought they were running out of chances, he replied: "No, I don't feel like that at all.
"Once March is out of the way, we play Manchester United away and then Arsenal away, then we have seven games. We shall see where we are at the end of March and then go from there.
"You never know, we will wait and see. If we can get ourselves on some kind of run [we'll be ok].
"Back-to-back wins for QPR has got them right back among it and if you ask Harry Redknapp the question about his team, absolutely he'll think they can stay in this league."
|VILLA ARE CONFIDENT - LAMBERT
|40/1||The Villans are 40/1 with BetVictor to find form and secure a top-10 finish in the Premier League
"[It was] disappointing, that certainly hurts," he added. "We got ourselves into the lead and then they score virtually straight after, so we need to hold our hands up to that.
"We need to be better and see the game out, and we didn't do that. We have to look at ourselves and I know that, the players know that."
Villa boss Paul Lambert, on the other hand, was delighted with the win that lifts his team out of the bottom three, claiming they will be safe if they can replicate Saturday's form for the remainder of the season.
"I though we deserved to win the game," he said. "It was a massive game, everybody knew that, the players didn't look like a side lacking in confidence.
"They know the pressure is there. If we keep doing what we're doing we'll be alright."