The visitors carried an impressive five-match unbeaten run into this contest and looked the more impressive side in the opening stages again here.
They made that superiority pay inside five minutes, as after being allowed too much space on the edge of the area, John Swift swept past John Ruddy to put the Baggies in front.
After falling behind to something special, John Eustace’s men relied on a stroke of luck to level proceedings.
While it appeared Koji Miyoshi slipped and fell into Cédric Kipré rather than being fouled, a penalty was awarded regardless, and Juninho Bacuna dispatched from 12 yards.
The Blues had failed to come back to win in their previous 46 games after conceding first, but they took a big step to correcting that as they hit the front before the interval. Cody Drameh’s sumptuous cross was looped home by the unmarked Dion Sanderson, leaving the visitors with plenty to ponder at HT.
Carlos Corberán was now the manager in need of a response, and his side controlled proceedings in the early going of the second period. He was left exasperated as his side spurned a chance to level the score, as after Darnell Furlong ghosted into the box unmarked, the wing-back dragged his effort wide.
Birmingham failed to learn their lesson as Furlong was allowed to sneak in at the back post again a few minutes later, but this time Siriki Dembélé did just enough to put him off.
The visitors toiled in their efforts to find a way back into the game, but eventually their wastefulness was punished as the Blues put the game to bed.
Three minutes from time, Gary Gradner curled an inch-perfect free kick into the top corner to seal the victory with his first Birmingham goal since April 2022.
Eustace’s men leapfrog West Brom into the top six, while the Baggies lost for the first time since early September - a sickener after leading so early.
Flashscore Man of the Match: Juninho Bacuna (Birmingham City)
