Birmingham missed a first-half penalty then conceded the only goal of the game shortly after the break for a 1-0 defeat at Braga.
Birmingham enjoyed a dominant opening period but wasted the chance to capitalise when Nikola Zigic had a penalty saved after Wade Elliot was fouled.
Braga then took the initiative and scored the winner with a deflected strike from Hugo Viana. The Portuguese then had further opportunities to seal the win as the visitor’s faded.
Championship Birmingham can still qualify if they beat Maribor at home next month.
Referee: Markus Strömbergsson (SWE)
Venue: Estadio Municipal de Braga
Braga scorers: Hugo Viana 51
TRIBAL ASKS: Will Birmingham’s European adventures adversely affect their attempts to get out of the Championship at the first attempt?
Yellow cards: Ewerton (BRA), Alan (BRA), Caldwell (BIR), Burke (BIR)