Both second string managers chose an array of regular first teamers in their starting line-ups for the Barclays Premier League (north) clash at The Hawthorns.
Blues started the brighter and Clinton Morrison wasted two excellent opportunities to give Keith Bertschins side the lead inside the first 20 minutes.
Darren Anderton then squandered the best chance of the first half when on the half-hour mark he shot straight at Baggies keeper Thomasz Kuszczac when put clean through on goal by Robbie Blake.
Just past the hour mark Blake himself was guilty of wasting a great chance. Former Blues defender Darren Purse clearing his close range effort off the line on this occasion.
Rob Earnshaw then went close for the Baggies before, on 68 minutes, the home side scored what proved to be the deciding goal.
Baggies midfielder Jason Koumas made a mazzy run into Blues territory before laying the ball onto the onrushing Lloyd Dyer whose well hit shot beat Vaesen in the Blues goal.
Dwight Yorke almost snatched a point for Blues but his well hit shot from just outside the box was superbly saved by Kuszczak in the closing stages.
The 1-0 defeat leaves Blues in 5th place in the Reserves League table.
West Brom: Kuszczak; Dyer, Purse, Moore, Scimeca; Chaplow, Marshall (Davies, 46), O'Connor; Koumas, Elvins, Earnshaw. Subs not used: M Jones, Forsyth, Hodgkiss, Nicholson.
Blues: Vaesen; Alsop, Oji, Martin Taylor, Parratt; Nafti (Till 83), Diao (Painter 82), Anderton; Yorke, Robbie Blake, Morrison. Subs not used: Kuqi, Asa Hall, Birley.
For Reserves League table, click here