Huddersfield pushed West Brom further into the relegation mire and strengthened their own chances of Premier League survival with a 2-1 victory at The Hawthorns on Saturday.
After a goalless first half, two goals in eight second-half minutes from Rajiv van La Parra (48) and Steve Mounie (56) put Huddersfield in control.
A Craig Dawson header (64) offered West Brom a route back into the game, but the visitors held on to heap the misery on Alan Pardew and his side.
With 10 league games remaining, West Brom are bottom of the table and seven points from safety, while Huddersfield move up to 14th, three points ahead of 18th-placed Swansea.
After a turgid first quarter, the game sparked into life with Jay Rodriguez spurning the first real opportunity when failing to connect with James McClean's low corner.
Alex Pritchard then saw an attempt blocked by the head of team-mate Mounie, who was standing some two yards out following Florent Hadergjonaj's cross, while Ben Foster did superbly to block the follow-up shot from Van La Parra.
Just before half-time, it was West Brom who should have broken the deadlock, but the unmarked McClean could only volley over from Matt Phillips' chipped ball in.
Huddersfield were rewarded for a bright start to the second half when Van La Parra latched onto Collin Quaner's low cross.
The visitors doubled their lead eight minutes later, with Alex Pritchard playing a defence-splitting pass for Mounie, who curled the ball around the onrushing Foster.
Dawson did head West Brom back into contention with half an hour to go, but the defender was then guilty of a missed opportunity late on, as he could only shoulder the ball over from three yards out when looking to meet another corner.
Opta stats
- Huddersfield Town have won back-to-back Premier League games for the first time since their opening two fixtures of the season.
- West Bromwich Albion are the first side the Terriers have ever done a Premier League double over since reaching the competition.
- Under Alan Pardew, West Brom have accrued just eight points in 14 Premier League matches (W1 D5 L8), four fewer than their first 14 games of the campaign before his arrival (W2 D6 L6).
- Rajiv van La Parra has scored two of his three Premier League goals against the Baggies (67%).
The managers
Alan Pardew: "Three wins in 37 games says it all really - we've got to find a way. However we get it, maybe it can spark us into life. We've got players who can perform better than they have done today. We need to bring those performances to the pitch somehow.
"You have to persist in your values and in what you think is right," Pardew added. "We'll set our team up as strong as we can next week and try a game of football."
David Wagner: "It's a massive win, of course it is. I spoke before about how important this game is, that it's a final for both teams. We won it and we are delighted for all the supporters, the players and all the backroom staff, for all the effort they brought from training onto the pitch.
"It was a final for both teams. We came over this period of the first five, 10 minutes without conceding a goal, even if they didn't have the clear-cut chances.
"It was an open game. In the second half we scored two wonderful goals and kept them away from goal, as good as possible.
"We know how strong they are from set-pieces and they scored one from a corner. Something you like to avoid but it's not always possible - it's a wonderful afternoon for us."
The pundit - Paul Merson
Man of the match - Rajiv van La Parra
In a tightly-contested game, it was Van La Parra and Pritchard's willingness to take the game to West Brom after the break which ultimately put the game beyond the hosts.
And while Pritchard got himself an assist, it was Van La Parra who scored the vital opener, adding to the goal he scored in the 1-0 win when the teams met back in November.
The Dutchman could have had a second later on, only to be denied by the feet of Foster, while a match-high six tackles shows it wasn't just in attack where Van La Parra flourished. Victory will feel extra sweet for the former Wolves player.
What's next?
It's a week until both sides are back in Premier League action. West Brom travel to Watford next Saturday for a 3pm kick-off, while Huddersfield head to Wembley to take on Tottenham at the same time.