Match ends, Watford 1, Queens Park Rangers 2.
Queens Park Rangers came from behind to clinch a late win at Watford and dent the Hornets' automatic promotion bid in the Championship.
Troy Deeney smashed home from the penalty spot to put the hosts ahead early in the second half after Ismaila Sarr was brought down by Geoff Cameron.
But Charlie Austin headed in Chris Willock's cross to level.
And Albert Adomah's composed finish in the 90th minute saw Rangers end Watford's four-match unbeaten run.
Watford's bid for an immediate return to the Premier League has been built on their home form, winning 10 of their first 13 league games at Vicarage Road.
In a first half of few clear chances, Hornets centre-back Francisco Sierralta saw his header pushed onto the bar by visiting keeper Seny Dieng.
And the hosts looked to be on their way to a fourth successive home win when Deeney netted his third goal in four games.
Yet substitute Willock dug out a cross from the right which Austin converted from eight yards out to score his second goal since re-joining the R's on loan from West Brom last month, and his 50th goal for the west London club.
Rangers then completed the turnaround when Adomah brilliantly controlled a ball into the box from right-back Todd Kane and turned it past Hornets keeper Daniel Bachmann from close range.
The Hoops' third straight away win lifts them to 17th and seven points clear of the relegation zone, while Watford are fifth, three points off the top two.
Watford manager Xisco Munoz:
"I am responsible for today's game. I don't know why but we played without intensity. It was my mistake. We knew today was an important game for us but we were not at our best level.
"We can only say we will continue and we have another game soon. We need to improve and work harder - and we need to learn from the mistakes of today.
"It was my mistake because I did not give important words before the game and we started without intensity and ambition, and our passion. Without this intensity it is impossible."
QPR boss Mark Warburton:
"I thought it was a strong second-half performance, especially after going down to a penalty. We were masters of our own downfall, in terms of giving the ball away led to the penalty.
"It was very similar to Norwich away - we responded very well and got the rewards.
"It was their reaction that was so pleasing - they didn't sit back and accept the draw, they were on the front foot and it was a well-deserved victory in the end."
- 32NavarroBooked at 90mins
- 31SierraltaBooked at 54mins
- 3NgakiaSubstituted forWilmotat 83'minutes
- 14ChalobahSubstituted forZinckernagelat 83'minutes
- 19HughesSubstituted forSemaat 67'minutes
- 10João PedroSubstituted forGrayat 67'minutes
- 14JohansenSubstituted forWillockat 67'minutes
- 3WallaceBooked at 33mins
- 10ChairSubstituted forAdomahat 82'minutes
- 7BonneSubstituted forThomasat 89'minutes
- 45AustinSubstituted forKelmanat 82'minutes
- Jarred Gillett
- Shots on Target
Second Half ends, Watford 1, Queens Park Rangers 2.
Offside, Queens Park Rangers. Albert Adomah tries a through ball, but Lee Wallace is caught offside.
Attempt missed. Albert Adomah (Queens Park Rangers) right footed shot from the left side of the box is too high. Assisted by Chris Willock.
Marc Navarro (Watford) is shown the yellow card for a bad foul.
Lee Wallace (Queens Park Rangers) wins a free kick in the defensive half.
Foul by Marc Navarro (Watford).
Goal! Watford 1, Queens Park Rangers 2. Albert Adomah (Queens Park Rangers) right footed shot from very close range to the bottom left corner. Assisted by Todd Kane with a cross.
Substitution, Queens Park Rangers. George Thomas replaces Macauley Bonne because of an injury.
Foul by Chris Willock (Queens Park Rangers).
Ismaila Sarr (Watford) wins a free kick on the left wing.
Albert Adomah (Queens Park Rangers) wins a free kick in the defensive half.
Foul by Philip Zinckernagel (Watford).
Attempt missed. Lee Wallace (Queens Park Rangers) left footed shot from the left side of the box misses to the right. Assisted by Chris Willock with a cross.
Offside, Queens Park Rangers. Charlie Kelman tries a through ball, but Albert Adomah is caught offside.
Dominic Ball (Queens Park Rangers) wins a free kick in the defensive half.
Foul by Andre Gray (Watford).
Substitution, Watford. Ben Wilmot replaces Jeremy Ngakia.
Substitution, Watford. Philip Zinckernagel replaces Nathaniel Chalobah.
Substitution, Queens Park Rangers. Charlie Kelman replaces Charlie Austin.