A second half goal by giant Nicola Zigic was enough for Birmingham to beat a Hammers side that looked entertaining but could not deliver any end product.
Summing up the defeat, manager Avram Grant admitted his side were not quite at the races.
“I think the tempo of the game disappointed me most,” Grant told the official site. “We’re used to playing with a higher tempo and a high confidence and we didn’t influence the game as we know we can.
“It’s the first game we’ve lost to a team near us. Most of the games [against our rivals] we’ve taken points from so today it was very important. We could have won the game in the first half but we didn’t. Then we didn’t deal well with the set-pieces.”
“They have done very well against us. They’ve used Zigic and the tall players very well and unfortunately we lost.
“Of course they scored from two corners in the semi-final and they scored here. I’m not happy about this. We need to deal with this. Larsson is good and the delivery is very good but we need to deal better with this.”