Albion, now deep in relegation trouble, could easily have suffered a heavier defeat but for the brilliance of Russell Hoult who repeatedly denied Villa's persistent attack.
The difference in class between the two teams was quickly evident as Villa launched a series of attacks.
There was a great deal of determination about Villa as they were obviously intent on making amends for their 1-0 home defeat at the hands of Newcastle last week.
With Gareth Barry, Lee Hendrie and Thomas Hitzlsperger pushing forward Albion were in serious danger of being over-run.
Referee Mike Dean moved a free-kick ten yards closer to Albion's goal following dissent by Koumas who was booked for his trouble.
Hendrie nudged the ball to Hitzlsperger and the young German blasted his shot into the defensive wall. The ball cannoned into the path of Vassell to show with a low shot to the right of Hoult.
Albion were indebted to Hoult six minutes later when the goalkeeper further enhanced his claims for international consideration with a fine save from a Dion Dublin header.
It proved to be a crucial save because in the 29th minute Albion got back on to level terms when Jason Koumas equalised with a low drive after the luckless Staunton had blocked a Lee Hughes shot.
Albion appeared to be heading for a hard earned draw when Hitzlsperger grabbed the ball to score the winner with a swerving 20-yard drive in stoppage time.