A controversial penalty from David Cotterill heaped more misery on faltering Birmingham and put Sheffield United's promotion bid back on track with a 2-1 win at Bramall Lane.
Danny Webber had put Kevin Blackwell's side in front just before half-time, firing home from close range following a knockdown from Darius Henderson, who appeared to be marginally offside.
An own goal from Blades skipper Chris Morgan 17 minutes from time looked to have given Alex McLeish's stuttering side a point. But referee Lee Mason pointed to the spot with nine minutes remaining to give Cotterill the chance to slot home the resulting spot-kick to give United three precious points.
Birmingham came into the game knowing a victory would take them level on points with leader Wolves, but once again a shortage of goals was their downfall.
Blues have now won just two of their last 10 games, while the Blades are up to fifth, six points behind Alex McLeish's side with a game in hand.
United came close 12 minutes before the break when Henderson's header was cleared off the line by Stephen Carr and Danny Webber headed the rebound straight at Maik Taylor.
But they were in front three minutes before half-time when Henderson headed the ball into the path of the unmarked Webber, who smashed the ball past Taylor.
But the visitors were level with 17 minutes remaining with goal that came out of the blue.
Full-back David Murphy was allowed too much space on the left and United were made to pay as he whipped in an inviting cross that was turned into his own net by the unfortunate Morgan.
But the Blades restored their lead nine minutes from time when on-loan striker Craig Beattie tumbled in the area following minimal contact from Carr and Radhi Jaidi. And Cotterill held his nerve to send Taylor the wrong way from the spot.
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