Three goals before half-time for Manchester City condemned Albion to a routine defeat at the Etihad Stadium.
Graham Dorrans scored a superb goal for the Baggies on 15 minutes to halve the hosts’ lead to 2-1 and give Pepe Mel’s side a glimmer of hope.
But a Martin Demichelis goal before the interval sealed the City win after Pablo Zabaleta and Sergio Aguero had fired them 2-0 ahead inside 10 minutes.
Albion went behind in just the third minute when keeper Ben Foster parried a shot from Sergio Aguero and Zabaleta headed home the rebound.
And, after missing a fine chance to score from a Nasri cross, Aguero doubled the lead in the 10th minute when he side-stepped Morgan Amalfitano’s challenge and curled a fabulous shot past Foster.
Albion had a goal dubiously disallowed for offside against Billy Jones, with Matej Vydra’s neat finished rendered irrelevant.
But they got back in the game on 15 minutes as Liam Ridgewell and Stephane Sessegnon set up an counter-attack and Vydra squared for Dorrans, who beat Gael Clichy superbly with a chip and then scored past a helpless Joe Hart.
But it was 3-1 nine minutes before half-time when a corner from Samir Nasri was flicked on by Vincent Kompany and, with Liam Ridgewell and Jonas Olsson caught ball-watching, Demichelis stole in at the far post for the simplest of finishes.
The Baggies might have grabbed another goal on the stroke of half-time when Billy crossed for Sessegnon, but Komany did enough to divert his shot over the bar for a corner with a fine last-ditch challenge.
Early in the second half City threatened again down their right flank through Zabaleta, who delivered a dangerous cross towards Edin Dzeko, forcing Foster into a crucial intervention with his feet.
At the other end, Amalfitano was less precise with his centre after finding space on the Baggies right, with Hart making a comfortable catch.
And Albion had another let-off just before the hour-mark when Zabaleta found room on the overlap for City and crossed to the near post, when Craig Dawson made a vital interception to prevent Dzeko turning the ball past Foster.
Albion did their best to find another lifeline but their efforts were limp.
Amalfitano, who had struggled to impose himself on the game, was closest to forcing a breakthrough, first with a low shot that looked to be testing Hart until it was blocked in the area by Javi Garcia, then with a curling effort from outside the area that was parried to safety by the home keeper.
Substitutes Saido Berahino and Victor Anichebe almost combined with 10 minutes to go when Berahino fired a neat ball towards the feet of his fellow substitute, but Anichebe lost his footing and the chance petered out.
And in the closing stages Ridgewell cut in from the left and curled in a right-footed effort which Hart had to scramble away as Berahino closed in.