Birmingham boss Alex McLeish criticised his side for "losing the plot" in the 2-1 defeat at Wigan.
Maynor Figueroa struck in the second of five added minutes to snatch all three points and give the Latics' Barclays Premier League survival battle a much-needed boost.
But McLeish was disappointed with the way in which they conceded the late goal, especially as he felt they should have had a penalty minutes earlier for an Antolin Alcaraz challenge on Curtis Davies.
"We started the game so well but when we lost the goal we seemed to lose the plot," he said.
"Figueroa's right leg is only usually for standing on but he threw his weight behind it and how it went in is a mystery.
"Ben Foster never saw it until late because the amount of bodies in his way. But how the referee doesn't see it is a penalty before that, I am baffled. Alcaraz does not look at the ball, he just takes the player out."