New ownership has stirred a wave of optimism that Birmingham continued to ride as Wigan stuttered again, the home side's disappointment compounded by more worries over Chris Kirkland's recurrent injury problems.
The 28-year-old goalkeeper, who has been in outstanding form lately, had to be replaced after 24 minutes when he suffered a back spasm. After his performance against Sunderland last week, when the former Wigan manager Steve Bruce said that Kirkland would have made the England jersey his but for doubts over his fitness, the timing of this setback could not have been worse.
Kirkland will be assessed over the next few days, although his current manager, Roberto Martinez, is more worried by what he described as Wigan's collective "lack of character" after they surrendered a 1-0 half-time lead.
Charles N'Zogbia had put them ahead in the 33rd minute, curling a fine left-foot shot beyond Joe Hart. The goal was a just reward for Wigan. But for Hart's saves from Paul Scharner and Hugo Rodallega, the game might have been put beyond Birmingham's reach.
But Alex McLeish's side, cheered on by their new owner, Carson Yeung, and his entour-age, rediscovered the spirit and confidence that has earned them a six-match unbeaten run and eighth place in the Premier League. "We felt if we could get a goal we could go on and win the game," McLeish said. "At 1-1 you could see the urgency in our players, and I think that unnerved Wigan."
Sebastian Larsson, Birmingham's deadball specialist, levelled the scores after an hour. His free-kick from wide on the left, meant as a cross, found the net unaided, with its intended target, Scott Dann, failing to make contact but doing enough as he and Scharner jumped together to distract the substitute goalkeeper, Mike Pollitt.
Wigan tried to reimpose themselves but were caught on the break five minutes later, a chip over the top from the hard-working Lee Bowyer allowing Christian Benitez to steal a yard on Titus Bramble before unleashing a shot Pollitt might have saved.
After Bramble had brought down Cameron Jerome, Larsson swung the ball into the left-hand corner from a free-kick just outside the box. Pollitt was blameless this time.
Martinez sent on Jordi Gomez, his former Swansea midfielder, with 13 minutes left and the Spaniard emulated Larsson in putting away a direct free- kick, but Wigan's recovery came too late.
"We needed to score a second goal to kill the game and we didn't," Martinez said. "We knew Birmingham would come back at us but we did not show the character to impose ourselves when they were chasing the game, and that is something we have to address."
Referee: Lee Probert
Man of the match: Bowyer
Match rating: 7/10