An out-of-sorts Watford lost ground on the automatic promotion spots after they were beaten 2-0 at Huddersfield.
The Hornets have now dropped down to fifth after an error-strewn display in West Yorkshire.
Both Huddersfield goals were gifted to them, thanks to clangers from Ben Foster and Etienne Capoue, with the latter scoring an own goal after Fraizer Campbell's opener.
Town have now won four consecutive home games and are just five points shy of the play-off positions.
Huddersfield started the brighter but would not have expected Watford to gift them the opener after just nine minutes.
Goalkeeper Foster dawdled on a backpass from Ben Wilmot, allowing Isaac Mbenza to chase him down in the box.
The veteran's attempted clearance only ricocheted off the shins of Mbenza and into the path of Campbell who gleefully tapped into the empty net.
At the other end there was goalkeeping of a completely different kind when Town's Ryan Schofield pulled off a superb reaction stop to deny James Garner.
The Manchester United loanee looked destined to score when the ball fortuitously fell his way just a few yards out, but Schofield was alert enough to keep him at bay.
That miss made it all the more perplexing as to why Troy Deeney was named among the substitutes for Watford, especially after a purple patch that had seen him score in each of his last three outings.
They could certainly have done with Deeney's finishing as Tom Cleverley, Capoue and Andre Gray all saw chances go amiss.
Watford were indebted to Christian Kabasele just after the half-hour mark when the centre-half got back just in time to get a block in on Mbenza.
But from the resulting corner the hosts doubled their advantage - and in comical circumstances, as Mbenza's inswinger was sliced into his own net by Capoue.
It could have got worse just before the interval when Juninho Bacuna's goal-bound effort was well-blocked by the back-tracking Garner.
Carel Eiting tested Foster's concentration just after the restart with a side-footed shot from outside the box.
Watford had plenty of the ball after the break but were finding Town's defence hard to get past. Gray worked his way through just before the hour but was denied by a sprawling save from Schofield.
Capoue blazed over shortly after for the below-par Hornets, who were bossing possession but struggling to make many inroads.
Sub Alex Pritchard blazed over for Town in the final quarter of the game but the two-goal buffer proved more than enough as the hosts ran out worthy winners.
What the managers said
Huddersfield's Carlos Coberan: "We knew the level of quality that Watford have and I was expecting a tough game but our effort and commitment was amazing.
"It's hard to find one player that didn't play with the correct enthusiasm and desire. Ryan Schofield played well but for me to individualise just one player would not be fair as I cannot say that Campbell or (Lewis) O'Brien were less important, for instance.
"The merit of this positive results we are getting is for the players."
Watford's Vladimir Ivic: "We had problems right from the beginning. We made mistakes early on and we paid for these two mistakes with the two goals Huddersfield scored.
"We created more in the second half and were more dominant but as I say our problems started from the first minute. We created some chances but were without any ideas and confidence in the first half. We need to do much better."