Albion suffered their first home defeat since April on Tuesday night, losing 1-0 to Middlesbrough at The Hawthorns.
Hayden Hackney’s second-half goal earned Boro all three Sky Bet Championship points in B71.
Carlos Corberán’s team will try and bounce back this weekend when they host Millwall.
The boss made two changes to his XI, bringing in Alex Mowatt and Jed Wallace for Ousmane Diakite and Tom Fellows.
An early stoppage saw assistant referee Rob Smith receive medical treatment before being replaced by fourth official Jacob Miles - and leaving with the best wishes of all four stands.
Middlesbrough threatened for the first time around the 25-minute mark, Alex Palmer saving Finn Azaz’s effort and Riley McGree skewing his rebound over. Albion’s No.1 then needed to be at his best again soon after, superbly keeping out Emmanuel Latte Lath’s nod towards goal.
The home side improved following those scares and began to create chances themselves, as John Swift curled over and Jed Wallace saw a side-footed finish well stopped inside the area.
There was one final opportunity during first-half stoppage time via an Albion counter-attack, but Wallace’s shot at the end of a quick move landed wide.
The game halted during the 57th minute to pay tribute to Baggies fan Mark Townsend, who sadly passed away on Saturday, with the whole stadium participating in a period of applause.
Openings were pretty scarce until just after the hour mark - Boro twice going close through Luke Ayling and Latte Lath headers, and Palmer also smartly keeping out a Ben Doak attempt.
There was nothing the Baggies ‘keeper could do about Middlesbrough’s goal, though, Hackney guiding one into the bottom corner and handing them the advantage.
Corberán’s men attempted a response and almost found it eight minutes from time, however Josh Maja couldn’t quite guide his poke home despite Dieng already being beaten.
And Maja hammered into the side netting in a late onslaught where, unfortunately, Albion were unable to draw level.
Albion: Palmer; Furlong, Bartley, Ajayi, Heggem (Styles 78); Racic (Molumby 63), Mowatt; Wallace (Fellows 54), Swift (Johnston 63), Grant (Dobbin 78); Maja.
Substitutes: Wildsmith, Holgate, Diakite, Cole.
Attendance: 23,769 (1,076).