Stuart Parnaby gave Blues second string the lead five minutes into the second half of the game at Brentford's Griffin Park Ground.
Robert Gradwell scored Blues' second seven minutes from time.
Blues Res: Colin Doyle; Mat Sadler, Franck Queudrue, Radhi Jaidi (Asa Hall 46), Olivier Tebily; Jordon Mutch. Sebastian Larsson (David Howland 55), Damien Johnson, Stuart Parnaby; Robert Gradwell, Jamie Sheldon (Jake Jervis).