Norwich loanee Daniel Sinani condemned faltering Championship contenders West Brom to a fourth straight away defeat.
The Terriers’ striker slid in from close range to leave Valérien Ismaël’s side eight points off the coveted automatic promotion places.
Victory means Town have gone five games without defeat at Alfred Mcalpine Stadium.
Captain Jake Livermore was also shown a straight red card on a miserable afternoon for the visitors.
It was the Albion’s high defensive line that proved their downfall as the Terriers ripped them apart early on.
Scott High threaded a clever ball to free Danny Ward who rolled the ball across goal to allow Sinani a tap-in after just six minutes.