QPR lost further ground on Championship leaders Leicester after being held to a goalless draw at Watford.
The result leaves QPR five points behind City and one point off the automatic promotion places.
The visitors managed just one on-target attempt in a game devoid of good goal-scoring chances.
The best chance of the game fell Watford's way early in the second half when Diego Fabbrini forced Robert Green into a smart save.
Fabbrini played a one-two with Troy Deeney but he was unable to beat Green with his angled attempt from eight yards.
The draw means Giuseppe Sannino remains unbeaten after three games as Watford's head coach with his side conceding just one goal in that time.
Rangers came into the match with Charlie Austin still sidelined through injury, so Redknapp chose to deploy Niko Kranjcar as the focal point of the attack.
The Croatian sent a couple of attempts narrowly wide of Manuel Almunia's left-hand post while Matt Phillips dragged a shot wide in a low-key opening half.
With around 10 minutes remaining Watford's Sean Murray tried two long-range strikes in quick succession - the first was blocked before his next right-footed effort from around 25 yards was safely held by Green.
It looked like the clear-cut chance both teams craved might fall to Andrew Johnson when a Phillips cross from the right found him completely unmarked in the area but the flag was already up for offside when he headed wide.
Watford head coach Giuseppe Sannino:
"It was a very good result against a very good team that we know was tipped to win the title.
"It is a very tough league. I knew and I can confirm that now because we've faced three different teams in different positions.
"Today, I knew it was difficult before the game and it was a good game against a good squad. I know that we have to improve - but we have time now to improve."
QPR assistant boss Kevin Bond:
"It's been the same old story for us. We came here and played without a centre-forward as such, a recognised striker, but we came with a plan which I thought worked really well and we really dominated the game in the first half.
"We had a couple of half-chances and Niko [Kranjcar] had a couple of shots from the edge of the box - but it's been our problem [scoring goals].
"Watford went a little bit more direct in the second half and the game opened up - but it was a game of very few chances."
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