West Brom's winless run stretched to six games as the Sky Bet Championship leaders suffered a 1-0 defeat at home to Stoke.
Striker Tyrese Campbell, whose father Kevin used to play for the Baggies, scored the only goal after nine minutes.
West Brom failed to force a serious save from Stoke goalkeeper Jack Butland, as their recent difficulties continued. Slaven Bilic's side have now taken just four points from their last 18 available – yet still lead the table by a point from Leeds.
Stoke moved four points clear of the relegation zone after securing successive away wins.
West Brom were dealt an early blow when left winger Grady Diangana, making his first start since December 14 following a hamstring injury, was left hobbling in only the second minute.
Kenneth Zohore replaced the on-loan West Ham winger in the fourth minute and worse was to follow for the hosts as they fell behind.
Nick Powell sent Tom Ince racing away and Ahmed Hegazi failed to clear, allowing the winger to square to Campbell, who steered the ball in from 10 yards out despite goalkeeper Sam Johnstone getting a good hand to the ball.
It was Campbell's fifth goal in nine league games for Stoke.
Sadly for Campbell, that was his last meaningful piece of action as he became the second player to limp off injured, Lee Gregory replacing him after 25 minutes.
Zohore went close for Albion when his angled curling effort from 22 yards flew inches over the bar.
Pereira was then a fraction away from an equaliser when his curling free kick from out wide sailed just wide with Butland at full stretch deep into stoppage time at the end of the first half.
West Brom started the second half as they finished the first, on top, as they kept pushing for an equaliser.
Hal Robson-Kanu's stooping header dropped wide after Zohore's lobbed centre, then Pereira's inviting cross was punched clear by Butland, before Zohore screwed his shot comfortably wide after a pacy, diagonal run.
Stoke had barely got out of their own half in the second period, but they hit Albion on the counter on the hour with the chance to make it 2-0.
Gregory could only sidefoot wide from six yards after a driving run by Allen.
Stoke had to defend for their lives in the last few minutes but their defence and Butland stood firm, the goalkeeper catching or punching cross after cross to preserve their clean sheet.