Huddersfield needed a 90th minute Tom Ince goal to overcome a Watford side, whose performance suggests they may already be on the beach.
The first half was a bit of a non-event with neither team creating any clear cut chances to speak of. Huddersfield, buoyed by a lively home crowd, started well with much of their play coming down the right hand side as Quaner and Hadergjonaj combined.
The home side were firmly in the ascendancy in the first quarter of an hour, and had a penalty appeal turned down after Quaner went down in the box. However, replays showed referee Craig Pawson had made the correct decision.
Watford eventually began to grew into the game as the half wore on, as Will Hughes and Abdoulaye Doucoure popped the ball around attempting to penetrate a well organised Huddersfield back line. The best chance of the half fell to Troy Deeney, who had a shot deflected wide for a corner after the ball had broken his way following a neat interchange in Watford's midfield.
The half was probably best characterised by Roberto Pereyra curling two corners straight out of play, it was no surprise when the next corner was taken by Will Hughes.
Watford came out for the second half looking more incisive with Will Hughes getting on the ball more often and looking to create, but his side's inability to deliver from a dead ball meant they would waste countless corners and free kicks in promising positions.
On the hour mark both sides made positive changes, with Watford introducing Richarlison for Kiko Femenia and Huddersfield bringing on Tom Ince in place of Collin Quaner. It would be the latter of the substitutions who would ultimately have the final say in what was a dour affair for the majority of the match.
The warning signs were there for Watford, whose lazy passing was giving Huddersfield plenty of impetus as legs grew tired. Eventually it was a looping ball back into the Watford box which would be their undoing. Zanka showed a remarkable presence of mind to cut the ball back to an onrushing Ince, who finished cooly.
This one won't go down as a classic by any means, but Huddersfield fans won't care, it's three points closer to Premier League survival.