First-half goals by Danny Batth and Sam Clucas gave Stoke a vital win in the Championship on Sunday to send the Potters four points clear of the relegation zone.
Defender Batth steered in the opener at the far post in the 11th minute against their lacklustre Midlands rivals before Clucas doubled the lead with an excellent finish from just inside the penalty area on the stroke of half-time.
Freefalling Birmingham are now 12 without victory and have lost their last four matches, scoring in only one of them and managing only one shot on target here.