The Cottagers are undefeated in their last four Premier League games and beat Tottenham Hotspur 1-0 last time out.
Karagounis told the club's official website: "We've played some great matches lately. We have managed to get a good run of form together, and as a result, we have rhythm – which is important.
"However, we can't rest on that, because every game has its own story to tell and we will take nothing for granted.
"We know that they [QPR] need the points, they're a team that are fighting for their Premier League survival. They really want, and need points."
Fulham are 10th in the Premier League, six points clear of the relegation zone.