Andi Weimann clipped home West Bromwich Albion's late winner to edge victory over Birmingham City.
The former Aston Villa striker met Darnell Furlong's low right-wing cross with a neat left-foot flick to settle a scrappy West Midlands derby.
It was Weimann's first goal for the club following his January move from Bristol City, to bring a surprise conclusion to what had looked destined to be a goalless draw.
But there were angry scenes at the final whistle as Blues substitute Juninho Bacuna complained to referee David Webb about alleged racist abuse from the home stand.