Matej Vydra scored twice and won a penalty as Watford cemented their place in the top six and left Huddersfield without a league win in 12.
Troy Deeney opened the scoring from the penalty spot at the end of the first half after Callum Woods fouled Vydra.
The Czech international then doubled the lead when he converted an inswinging cross by Marco Cassetti.
He swept home his second before Cristian Battocchio scored his first Hornets goal with two minutes to go.
Reverse fixture and reverse fortunes
A late penalty from Troy Deeney gave Watford a 3-2 victory in the reverse fixture in September, and denied Huddersfield the chance to go top of the table, a far cry from their current position.
The best chance for the away side fell to Jermaine Beckford but his header was superbly saved one-handed by former Arsenal goalkeeper Manuel Almunia.
After beating Charlton in the FA Cup at the Valley, Huddersfield should have gone into the game full of confidence but the frailties, which have seen them fail to win a league match since 10 November, were evident.
Deeney, who was making 100th appearance for Watford, hit the bar for the home side before he had another effort cleared off the line.
Simon Grayson's team failed to heed the warning and handed the home side the perfect opportunity to open the scoring from the penalty spot and Deeney made no mistake.
Gianfranco Zola's men, who are the division's leading scorers, quickly added to their tally when Vydra stretched to meet an inviting cross from Cassetti.
He then made sure of the points when he scored his 16th goal of the season after Deeney this time turned provider and sent him clear.
Huddersfield, who now sit 18th in the Championship table, offered little in attack and Battocchio completed the scoring with a lovely flick into the back of the net with the outside of his boot.
Watford manager Gianfranco Zola:
"I just found out that this morning more than 100 supporters turned up here to help clear the pitch of the snow, so I think they've been rewarded with this performance and they deserved it.
"I think we've played some better games than this but it was a mature game. The result is a little bit too hard towards Huddersfield because in the first half they made it very, very difficult for us, so we had to work hard.
"I think the goal towards the end of the first half helped the team a lot because we then, in the second half, managed to play the football that we want to play. They had to open up a little bit more."
Huddersfield boss Simon Grayson:
"I thought, first half, we were well and truly in the game. We kept them quiet, you could sense the atmosphere had gone quiet as well and the decision just before half time changed the game.
"We let it affect us and it obviously gave them a big confidence boost. The decision was wrong, it's great tackle by our right back and it's outside the box, so it's a poor decision.
"But in the second half we felt sorry for ourselves and allowed Watford to dictate the game and when you do that against a team like Watford then you're under pressure because they're a good side."
- 01 Almunia
- 12 Doyley
- 27 Cassetti Booked
- 33 Nosworthy
- 39 Chalobah (Eustace - 61' )
- 40 Ekstrand
- 11 Forsyth
- 22 Abdi
- 38 Battocchio
- 09 Deeney (Geijo - 84' )
- 20 Vydra (Forestieri - 76' )
- 30 Bond
- 06 Hall
- 04 Eustace
- 07 Yeates
- 37 Mujangi Bia
- 36 Geijo
- 41 Forestieri
- 01 Smithies
- 02 Woods Booked
- 03 Dixon
- 05 P Clarke
- 06 Gerrard
- 32 Hunt
- 08 Clayton (Southern - 46' )
- 20 Danns
- 07 Scannell (Arfield - 79' )
- 18 Vaughan Booked (Novak - 57' )
- 21 Beckford
- 13 Bennett
- 15 Wallace
- 04 Norwood
- 16 Arfield
- 24 Southern
- 09 Novak
- 19 Lee
Live Text Commentary
Full Time The referee ends the match.90:00 +3:54
Almen Abdi produces a cross, Keith Southern makes a clearance.90:00 +2:01
Close range shot by Fernando Forestieri goes wide of the left-hand post.90:00 +1:09
The assistant referee flags for offside against Fernando Forestieri. Anthony Gerrard takes the direct free kick.89:32
Fernando Forestieri fouled by Calum Woods, the ref awards a free kick. Direct free kick taken by Craig Forsyth.88:28
Corner taken by Jack Hunt.88:18
The ball is delivered by Paul Dixon, Joel Ekstrand manages to make a clearance.85:38
Assist on the goal came from Marco Cassetti.85:38 Goal scored
Goal! - Cristian Battocchio - Watford 4 - 0 Huddersfld A goal is scored by Cristian Battocchio from deep inside the penalty area to the bottom left corner of the goal. Watford 4-0 Huddersfield.85:27
Centre by Marco Cassetti,84:14
A cross is delivered by Almen Abdi, Close range headed effort by Alexandre Geijo misses to the right of the target.83:36
Short corner worked by Fernando Forestieri.83:36 Substitution
Substitution Alexandre Geijo joins the action as a substitute, replacing Troy Deeney.83:23
Craig Forsyth crosses the ball, blocked by Calum Woods.82:46
The ball is sent over by Lee Novak, blocked by Nyron Nosworthy.82:28
The assistant referee signals for offside against Fernando Forestieri. Direct free kick taken by Peter Clarke.79:22
Jack Hunt delivers the ball.78:13 Substitution
Substitution Sean Scannell goes off and Scott Arfield comes on.75:00 Substitution
Substitution Matej Vydra leaves the field to be replaced by Fernando Forestieri.73:47
The assist for the goal came from Troy Deeney.
Goal! - Matej Vydra - Watford 3 - 0 Huddersfld Matej Vydra scores a goal from inside the penalty area low into the middle of the goal. Watford 3-0 Huddersfield.69:28
A cross is delivered by Paul Dixon, save made by Manuel Almunia.68:37
Free kick awarded for an unfair challenge on Jack Hunt by Craig Forsyth. Calum Woods restarts play with the free kick.66:52
Lee Novak is ruled offside. Manuel Almunia takes the free kick.66:04
Inswinging corner taken right-footed by Neil Danns from the left by-line to the near post, save by Manuel Almunia.65:56
The ball is swung over by Jack Hunt, Marco Cassetti makes a clearance.65:28
Corner taken by Neil Danns from the left by-line to the near post, Matej Vydra makes a clearance.64:22
Cristian Battocchio has shot on goal from just outside the penalty box which goes wide of the right-hand upright.63:01
Almen Abdi takes a outswinging corner to the near post, Keith Southern manages to make a clearance.61:19
The ball is sent over by Calum Woods, Jermaine Beckford takes a shot. Save by Manuel Almunia.60:21 Substitution
Substitution Nathaniel Chalobah leaves the field to be replaced by John Eustace.60:08
Centre by Cristian Battocchio, Paul Dixon manages to make a clearance.59:17
Neil Danns takes a shot. Save by Manuel Almunia.58:57
The ball is swung over by Sean Scannell, clearance by Craig Forsyth.58:49
Calum Woods produces a cross.57:33
Matej Vydra has an effort at goal from deep inside the area missing to the right of the target.56:50 Substitution
Substitution Lee Novak comes on in place of James Vaughan.56:05
The assist for the goal came from Marco Cassetti.56:05 Goal scored
Goal! - Matej Vydra - Watford 2 - 0 Huddersfld Matej Vydra scores a goal from inside the six-yard box to the top left corner of the goal. Watford 2-0 Huddersfield.55:47
A cross is delivered by Marco Cassetti,53:57
Nathaniel Chalobah fouled by Jermaine Beckford, the ref awards a free kick. Joel Ekstrand restarts play with the free kick.53:33
Neil Danns concedes a free kick for a foul on Nathaniel Chalobah. Free kick taken by Nathaniel Chalobah.49:11
Foul by Craig Forsyth on Jack Hunt, free kick awarded. Free kick taken by Alex Smithies.45:01
The match restarts for the second half.45:01 Substitution
Substitution Keith Southern comes on in place of Adam Clayton.45:00 +7:21 Goal scored
Goal! - Troy Deeney - Watford 1 - 0 Huddersfld Placed penalty scored by Troy Deeney. Watford 1-0 Huddersfield.45:00 +6:22 Booking
Booking Calum Woods is cautioned by the ref for unsporting behaviour.45:00 +6:09
Calum Woods challenges Matej Vydra unfairly and gives away a Penalty.45:00 +4:16
Marco Cassetti has an effort at goal from outside the area which goes wide right of the goal.45:00 +3:14 Half time
Half Time The whistle is blown to end the first half.45:00 +2:56
Matej Vydra decides to take a short corner.45:00 +2:47
Matej Vydra sends in a cross, James Vaughan gets a block in.45:00 +2:19
Inswinging corner taken right-footed by Matej Vydra from the left by-line to the near post, clearance made by James Vaughan.45:00 +0:27 Booking
Booking Booking for Marco Cassetti for unsporting behaviour.44:37
Troy Deeney takes a shot.43:57
James Vaughan challenges Lloyd Doyley unfairly and gives away a free kick. Free kick taken by Manuel Almunia.42:57
The referee blows for offside. Alex Smithies restarts play with the free kick.40:39 Booking
Booking James Vaughan goes into the referee's book for unsporting behaviour.39:59
Unfair challenge on Cristian Battocchio by James Vaughan results in a free kick. Direct free kick taken by Manuel Almunia.37:17
Troy Deeney concedes a free kick for a foul on Peter Clarke. Free kick taken by Peter Clarke.35:56
Neil Danns delivers the ball, Craig Forsyth gets a block in. Inswinging corner taken by Paul Dixon.35:20
Free kick awarded for a foul by Troy Deeney on Anthony Gerrard. Direct free kick taken by Anthony Gerrard.34:52
Centre by Sean Scannell, save made by Manuel Almunia.34:06
Long range shot by Nathaniel Chalobah goes wide right of the net.28:54
James Vaughan gives away a free kick for an unfair challenge on Cristian Battocchio. Nyron Nosworthy takes the free kick.27:16
Nathaniel Chalobah fouled by Adam Clayton, the ref awards a free kick. Nathaniel Chalobah takes the direct free kick.24:38
Craig Forsyth gives away a free kick for an unfair challenge on Jack Hunt. Free kick taken by Anthony Gerrard.24:25
The ball is delivered by Craig Forsyth, Peter Clarke makes a clearance.24:01
Jermaine Beckford challenges Nyron Nosworthy unfairly and gives away a free kick. Direct free kick taken by Nyron Nosworthy.23:12
Marco Cassetti sends in a cross, Anthony Gerrard manages to make a clearance.22:53
Marco Cassetti crosses the ball, Anthony Gerrard makes a clearance.22:25
Paul Dixon delivers the ball, save by Manuel Almunia.21:56
The ball is crossed by Craig Forsyth, Adam Clayton manages to make a clearance.21:07
James Vaughan takes a shot. Save by Manuel Almunia.20:42
Jack Hunt sends in a cross.19:00
The ball is crossed by Craig Forsyth, Calum Woods gets a block in. Inswinging corner taken right-footed by Almen Abdi played to the near post, Adam Clayton manages to make a clearance.18:05
A cross is delivered by Paul Dixon.16:34
Marco Cassetti gives away a free kick for an unfair challenge on James Vaughan. Adam Clayton takes the free kick.14:04
Troy Deeney produces a right-footed shot from deep inside the penalty box which goes wide of the left-hand post.13:18
Sean Scannell produces a right-footed shot from just outside the penalty box that misses to the left of the target.11:31
Jermaine Beckford is adjudged to have handled the ball. Nyron Nosworthy restarts play with the free kick.10:33
The ball is crossed by Marco Cassetti, clearance by Calum Woods.8:22
Paul Dixon produces a cross, blocked by Lloyd Doyley.6:39
Craig Forsyth takes a shot. Save made by Alex Smithies.6:25
The ball is swung over by Almen Abdi, clearance by Adam Clayton.4:05
Headed effort from deep inside the penalty area by Troy Deeney goes harmlessly over the crossbar.0:00
The referee gets the game underway.
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