Steve McClaren urged his players to do themselves justice against Watford in the FA Cup fifth round after QPR’s replay victory over Portsmouth.
Rangers will face the Premier League side at Loftus Road, where second-half goals from Nahki Wells and Matt Smith saw off Pompey.
Rangers are in the last 16 for the first time in 22 years.
And McClaren believes they are capable of causing an upset a week on Friday and securing a place in the quarter-finals.
The R’s boss said: “It’s the FA Cup and anything can happen.
“We’re at home, it’s Friday night under the lights and it’s an opportunity for certain individuals and the team to show themselves against Premier League opponents.
“Watford are a very good team and we’ll have to put in a top performance to get any kind of result.
“I just hope we put a performance in that justifies what we’ve been doing.
“This is an opportunity. We’ll be underdogs. I just want to make sure that the team gives a great performance.”
McClaren’s side had to be patient against Pompey, who troubled Rangers at Fratton Park but this time were very much second best and rode their luck before Wells broke the deadlock with 20 minutes remaining.
Darnell Furlong had headed against the bar as the hosts dominated large spells of the game.
It was therefore a win McClaren felt they thoroughly deserved.
“I think so. I would say it was a very professional performance,” he said.
“We started off very, very well. Pompey are a very good team and it took us a long while to break them down but in the end I thought our patience, discipline and attitude were really good.
“The fans have been talking about this game for about three weeks and it put a lot of pressure on us to win this.
“It was a tough one at Fratton Park and we’ve brought them back here and done the job.
“I’m delighted for the supporters because the FA Cup is important to them.”