QPR manager Steve McClaren praised his young players after a 2-1 victory at home to Leeds secured a place in the fourth round of the FA Cup.
Jake Bidwell's header from Luke Freeman's corner with 15 minutes remaining took Rangers through.
Aapo Halme had equalised for Leeds shortly after Aramide Oteh's first-half penalty.
Young forward Oteh was lively throughout, while the likes of winger Bright Osayi-Samuel and full-back Osman Kakay also impressed.
McClaren said: "With the penalty I was thinking 'Who's going to take this?' and Oteh grabbed the ball and stuck it away in front of the Leeds fans. He showed great courage – a great mentality.
"We've got a lot of injuries but this showed the depth of the squad. The youngsters have worked hard, had to wait for their opportunities, and this shows the future is bright.
"Cups are exciting and it gives our squad an opportunity, so long may it continue."
Incredibly, the win was QPR's first in the FA Cup without the need of a replay for 22 years and first in the third round for 23.
Not since Trevor Sinclair scored a famous overhead kick against Barnsley in 1997 had the R's gone through at the first time of asking.
McClaren said: "In the last few weeks we created history by winning at Nottingham Forest for the first time and now we're into the fourth round.
"But it's not just that, it's about a good performance and the result. I thought we deserved to win. We created a lot of chances and could have had more goals."
McClaren also defended goalkeeper Matt Ingram for a mistake which led to Leeds' goal.
Ingram, given a chance having been kept out by Joe Lumley this season, fumbled Lewis Baker's free-kick, enabling Halme to score from close range.
He did, however, produce a couple of important saves in the second half.
"For goalkeepers it's a very lonely business," McClaren said. "We wondered how he would react, not just under pressure from the opponents but from the (QPR) fans.
"He responded magnificently with one or two critical saves and did his job.
"He deserved his chance. He's been fantastic in training and apart from one slip he was tremendous here."
Leeds boss Marcelo Bielsa bemoaned his side's poor defending from set-pieces.
Goalkeeper Bailey Peacock-Farrell kept out two Bidwell headers from Freeman corners before the defender netted the winner.
"We lost because we didn't deal with some balls we should have dealt with. We didn't find the right solution from set-pieces," Bielsa admitted.
"We took decisions that were not useful for us and we didn't need to take those kind of decisions.
"When you look at the dangerous situations of the opponent, they have a common factor; when we lost the ball and on set-pieces.
"Apart from this aspect – the wrong passes and the set-pieces – we would look at the game and say our opponents did not deserve to win.
"Every week we designate a high percentage of our time to set-pieces. So we will look at what we have done wrong and try to correct it. You correct these things with experience.
"The performance from the players today was good. But we made too many mistakes and if you don't defend well then it is very hard to win games."