Rajiv van La Parra netted a stunning first-half winner as 10-man Huddersfield held on for another Premier League win to heap more pressure on West Brom boss Tony Pulis.
Van La Parra curled home the only goal just before half-time and although Christopher Schindler was sent off early in the second period, David Wagner's side produced more heroics to leave the visitors without a win in nine Premier League matches.
The Terriers, indebted to goalkeeper Jonas Lossl in stoppage time, beat Manchester United in their previous home game and this fourth league win of the season has lifted them five points clear of the Baggies, who have not won since mid-August.
Huddersfield and West Brom are priced up at 9/4 and 5/2 respectively in Sky Bet's relegation prices.
Swansea (1/2), Crystal Palace (4/5) and West Ham (2/1) are the three favourites to go down.
Post-match reaction
Huddersfield head coach David Wagner said his side's latest Premier League win was one for him and his players.
"I know that when we played Man United this was a big win," said Wagner.
"I think it was a big win for the football club, while today it was a big win for us as a group and for me as a manager.
"We've shown we can play in our identity and style and also, if we need to, we can play in the deeper block if necessary and I'm absolutely delighted the players have shown both."
West Brom boss Tony Pulis brushed aside the chants of 'we want Pulis out' that greeted him at the start of the second half.
The Baggies' winless run was extended to nine Premier League matches stretching back to mid-August, but the 59-year-old appeared unruffled.
"Anybody who's been on a run of games like we have, and we've been on a poor one in respect of results, you're going to take criticism," he said.
"I've been in the game a long time to know that's what happens, irrespective of who you are or what club you're at."
