Grady Diangana's goal saw West Brom move within three points of fourth-placed Leeds in the Championship with a 1-0 win over the Yorkshire side at The Hawthorns.
The DR Congo midfielder struck in the first half of a tight, breathless affair against a Leeds side who now have just one win in their past five games.
Whites manager Daniel Farke switched to three at the back on the hour mark in a bid to prise open a determined Baggies defence but, despite a late siege of the opposition goal, they could find no way through.
The home side could have won by more as Djed Spence kicked a Cedric Kipre shot off the line, although Leeds were denied a strong penalty claim when Kipre appeared to pull down Willy Gnonto as he shaped to shoot inside the box.