Troy Deeney recognised Watford had been "poor" and could easily have lost after they survived significant pressure to progress to the FA Cup quarter-finals with a 1-0 victory at QPR.
Javi Gracia's team moved to within one victory of reaching the final four at Wembley after being outplayed, scoring a fortunate goal through Etienne Capoue and then seeing their Championship hosts squander enough chances to build a convincing lead.
QPR had lost their five previous league fixtures, but, after making five changes to a winning team, Watford struggled and were consistently stretched.
Deeney told BT Sport: "We were poor in the first half, but had that bit of quality to score.
"We were in control, but weren't dominating or doing what we wanted to. We were sloppy at times. The character showed at the end with the way everyone dug in.
"We don't want to lose. We need to keep giving these performances. We are not playing that well, but are grinding it out. In older days we might have lost."
Gracia rested Ben Foster, Craig Cathcart, Abdoulaye Doucoure, Adrian Mariappa and Gerard Deulofeu, having made 11 changes for victories over Woking and Newcastle in the third and fourth rounds.
He said: "It wasn't our best game. But we knew before it would be very demanding to defend well, with long balls, second balls, set-pieces.
"Playing against QPR we have suffered a lot. So playing against a Premier League or a Championship team (in the quarter-finals) will very demanding.
"We are playing away a lot (in cup competitions). I want to play at home (in the next round)."
QPR's form is the Championship's worst, but, after an undeserved loss to Premier League opposition, manager Steve McClaren has renewed confidence in their ability to end their damaging run.
"It makes me hopeful," he said. "We're that close to turning it round, we've been very, very unlucky. We've got to keep that attitude and spirit.
"I'm so proud of the players' performances. It was their third game in six days. We couldn't have done anymore, apart from score.
"We lost the game by a set-play and Watford showed great resilience to get through, because we threw everything at them.
"Toni Leistner's chance at the end (in the 88th minute) summed us up. We were very close, but not close enough.
"I'm very disappointed with the goal. It's the only shot on goal I can remember and the only time I felt in trouble.
"We really started aggressively, but you have to score first in these games. Once you get a team like Watford holding the lead they're difficult to break down."
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