STOKE are not out of the woods yet, but the clearing is now more visible after this win.
Michael O'Neill's team moved four points clear of the drop zone with a solid performance against their managerless opponents.
It was a big improvement on the pitiful display that saw them trounced 5-0 at league leaders Leeds United on Thursday evening.
Stoke were inspired by an outstanding contribution from Nick Powell, whose creativity in midfield played a major part in Birmingham's downfall.
Sam Vokes rattled the bar with a header before Danny Batth (12 mins) and Same Clucas (45 mins) gave Stoke a much-deserved half-time lead.
Birmingham started the second-half a more determined outfit and their physical approach left its mark on several Stoke players, but the hosts held out well and go to Bristol City on Wednesday in much better shape.
In the light of Stoke's two concluding games involving clashes with strong promotion contenders - Brentford (third) at home and and Notts Forest (5th) away - the Bristol trip could be the Potters last chance to pick up an important point or three.
The kick off time for the Bristol game has been brought forward to 5pm.
Picture: Nick Powell was in outstanding form for Stoke.