The Latics ended the first half on top thanks to Charles N'Zogbia's brilliant goal - his second goal of the season.
But the Blues showed the grit that has served them so well in recent matches as two Larsson set-pieces sandwiched by Christian Benitez's strike took Alex McLeish's men into the top half of the table.
After a quiet opening, the game exploded into life when Hugo Rodallega and Roger Johnson clashed in an aerial battle which left the Birmingham centre-back in a bloody mess and resulted in a yellow card for the Wigan striker with the visitors demanding a red.
However, home boss Roberto Martinez was forced to shuffle his pack when England goalkeeper Chris Kirkland was carried off with a back injury and his replacement, Mike Pollitt, was called into action straight away to brilliantly deny Benitez.
But on 33 minutes Wigan edged in front when Rodallega - last week's match-winner against Sunderland - teed up N'Zogbia who fired a terrific curling shot into the top corner.
Despite playing the more attractive football, Wigan could not finish off the chances they were creating for their frontmen and it ended up costing them when the visitors drew level on the hour mark.
Larsson curled in a free-kick from the left-hand side and the ball eluded a clutch of players and Pollitt to fly straight in.
Just like they did at White Hart Lane two weeks ago, Wigan collapsed and they were behind within five minutes as their defence failed to deal with Lee Bowyer's long ball and Benitez fired past Pollitt.
Larsson's free-kick on 72 minutes took the Blues 3-1 ahead but the visiting fans were given a nervous finale when substitute Jordi Gomez curled in his own set-piece with a minute to go before they held on for a third straight win.