FA Premiership/ Aston Villa 3 Birmingham City 1: Championship football is the immediate prospect for Birmingham City after they slipped to their first Premiership defeat at Villa Park. The hope that followed a three-match unbeaten run has been drained at the home of their city rivals and it will take a huge effort to peg back a resurgent Portsmouth.

Birmingham are only three points behind Harry Redknapp's side, but the body language of the Blues players as they left the field was indicative of a team whose belief has been sapped. The loss of Matthew Upson in the warm-up, to what may be a ruptured Achilles tendon, was typical of the misfortune that has blighted Birmingham's season though his absence was no excuse for their shortcomings in front of goal.

Villa's penalty area was peppered with crosses as Birmingham sought a way back into a match that had slipped from their grasp after Gary Cahill's acrobatic superbly-struck goal restored the home side's advantage early in the second half, but Thomas Sorensen was rarely called upon to make a save. The Dane has made several gaffes in previous meetings between the clubs but here the humiliation was all Birmingham's. Villa's supporters did not miss their opportunity, goading their rivals with chants of "going down".

Birmingham have four matches left to prevent relegation, starting with Blackburn at home on Wednesday. Portsmouth, though, could have increased their lead to six points by then if they triumph at Charlton this afternoon.

Pompey's revival has clearly riled Bruce. "Again they're fortunate where they are playing against half a Middlesbrough team, half an Arsenal team, half a West Ham team - that helps," said the Birmingham manager. "But all credit to them. Four wins from six games is fantastic form."

Bruce's frustration was heightened by his grievances over Villa's first two goals, which he felt should have been disallowed. He argued, with some justification, that James Milner's boot was high when the Villa midfielder hooked the ball over the head of Mat Sadler before Milan Baros knocked in the first. Graham Poll waved play on, allowing Milner to feed Aaron Hughes whose low cross was rammed home by the unmarked Baros at the far post.

For the second goal Kevin Phillips had taken up an offside position before Cahill's spectacular score, though the Villa striker, arguably, was not interfering given that he made no contact with the initial delivery. "I think Villa got the key decisions," said Bruce. "In the derby games you need that little bit of luck and that went Villa's way today."

Chris Sutton's smartly-taken equaliser after 25 minutes had earlier given Birmingham some hope but Baros killed off any chance of a comeback with the home side's third goal, after some neat inter-play between Milner and Juan Pablo Angel. Bruce and Birmingham's misery was complete.

• Guardian Service