Steve Clarke's Baggies made it three wins in a row to move to fourth on the table and now sit just a point behind Roberto Di Matteo's Blues who have not won in four league outings.
Shane Long gave Albion the lead in just the 10th minute when he headed home James Morrison's floated cross from close range but Chelsea managed to level six minutes before the break through Eden Hazard.
The Belgian scored his fourth of the season with a well-hit, diving header from Cesar Azpilicueta's cross which managed to find its way past Boaz Myhill who was again deputising for the injured Ben Foster.
It appeared as though the goal could have got the Blues back on track but just six minutes into the second half, Peter Odemwingie netted the eventual winner with a header of his own, glancing in Long's cross at the near post for his fourth of the campaign.
West Brom now sit on 23 points from 12 outings - one behind Chelsea - and are looking extremely capable of grabbing more massive scalps this term under the guidance of Clarke.
The Hawthorns, West Bromwich - 25,933
Yellow cards:WBA - nil CHE - nil