Newcastle 0-1 Birmingham
Birmingham put the seal on a miserable week for Newcastle as David Dunn's second-half winner condemned the Magpies to a third home defeat in eight days.
Dunn converted the rebound after his initial penalty was saved by keeper Shay Given to maintain the Blues' unbeaten start to the season.
Newcastle, by contrast, have taken a solitary point from three matches and already their hopes of a title challenge appear forlorn.
This was a second Premiership defeat at St James' Park, and following their failure to qualify for the Champions League, Sir Bobby Robson's young side are struggling for form.
Desperate to make amends for their midweek disaster, they started brightly but were unable to breach a Blues rearguard which has yet to concede a goal.
Referee Matt Messias unintentionally struck the first blow, flooring Blues midfielder Robbie Savage with a flying elbow as he signalled a free-kick.
21 mins: John fires over
60 mins: Dunn scores after penalty saved
64 mins: Solano hits side-netting
United, with Gary Speed at left-back and Jermaine Jenas joining Kieron Dyer in midfield, broke swiftly after 11 minutes only for Dyer to have his shot blocked by Kenny Cunningham.
Hugo Viana sent the follow-up over the bar and the Portuguese winger put his side in trouble when he sent a back-heel inside his own box straight to Dunn, who forced Given to tip over.
Dunn was at the heart of Birmingham's best attacking forays, twice creating chances for Stern John before half-time.
But John sent the first effort over the top and then dragged his second shot wide.
Shearer endured a frustrating afternoon
Jenas picked up the game's first booking for a foul on Damien Johnson as Newcastle's frustration grew, Dyer drilling another long-range effort wide before the interval.
The home side dominated the early stages of the second half, forcing a succession of corners, but Ameobi could only head wide from Viana's cross and Shearer's powerful header was saved by Taylor.
Instead it was Birmingham who took the lead on the hour, Speed earning a yellow card after bringing down Johnson in the box as he raced onto Dunn's pass.
Dunn's initial penalty was weak, but Given could only spill the ball back to the midfielder who gratefully tucked away the rebound.
Solano went agonisingly close to an equaliser when he volleyed into the side-netting and later substitute Lee Bowyer had his shot well saved by Taylor.
As Newcastle pressed for an equaliser Birmingham might have grabbed a second, Dunn and Stan Lazaridis both going close on the break as the Geordie faithful roared their disapproval.
Newcastle: Given, Griffin, O'Brien, Bramble, Speed,
Solano (Bowyer 66), Jenas, Dyer, Viana (Robert 66), Shearer,
Ameobi (Chopra 66).
Subs Not Used: Harper, Hughes.
Booked: Jenas, Speed.
Birmingham: Taylor, Kenna, Upson, Cunningham, Clapham, Johnson,
Savage, Clemence, Lazaridis (Cisse 79), John (Horsfield 71),
Dunn (Tebily 88).
Subs Not Used: Bennett, Morrison.
Referee: M Messias (N Yorkshire).