The hosts sat in the relegation zone with just one win in 16 Barclays Premier League games coming into the match and looked set for another night of disappointment when Liverpool took a two-goal lead at Loftus Road. But goals from Shaun Derry, Djibril Cisse and Jamie Mackie secured a spectacular win for the west Londoners.
"It could be a defining moment and we have to make sure that it is," Hughes said after the match.
"I think we have been frustrated in recent weeks because we have felt things have gone against us. Things have been taken out of our hands. We haven't done too badly in games performance-wise but we haven't been able to get points on the board.
"From our point of view it was huge in terms of belief and what we will take out of the game. Now it is important we look to the weekend and make sure we don't let this go to waste."
Liverpool had looked on course for victory after Sebastian Coates' superb scissor-kick and a Dirk Kuyt effort put Kenny Dalglish's side 2-0 ahead.
The Reds manager was stunned by QPR's comeback and thought the hosts were recipients of the luck that eluded them last week when Clint Hill had a goal wrongly chalked off at relegation rivals Bolton.
"I don't think anyone saw it coming," Dalglish said. "The way we started the game was fantastic, the passing and the movement - the only thing missing was in front of goal.
"They came in at 0-0 at half-time and it could have easily been 3-0 or 4-0.
"You didn't even see them getting a goal. Maybe the luck they never got at Bolton, they got it tonight with a last-minute winner."
Source: PA
Source: PA