Slaven Bilic saw his side suffer a double penalty frustration at Old Trafford as Manchester United recorded their first home league win of the campaign thanks to a Bruno Fernandes spot kick.
Albion, searching for their first victory since promotion last summer, were awarded a penalty of their own soon after the restart after Fernandes appeared to trip Conor Gallagher.
But, after awarding it, referee David Coote overturned himself after re-viewing the incident on the pitch side monitor.
To compound the injustice - in West Brom eyes - Coote soon handed United the deciding penalty after a handball by Darnell Furlong although replays suggested Bilic was correct in claiming that Gallagher had been fouled by Fred in the build-up to Juan Mata's cross.