Boss Carlos Corberan admits West Brom were surprised by Birmingham but refused to blame goalkeeper David Button.
Hannibal Mejbri’s first senior goal – from a cheeky free-kick – and Krystian Bielik’s header sealed a comfortable 2-0 victory for the hosts.
Button was at fault for both goals, after being caught out by Hannibal before flapping at a corner to allow Bielik to score, but Corberan defended his goalkeeper.
“It would be easy to say we have lost because of David but I don’t think so,” he said, as Albion remained sixth in the Championship. “I know he is not going to be happy.
“What I proposed didn’t work, our attack couldn’t beat their defence.
“The team didn’t perform. It took more than the usual time to adapt and with the first goal they played a surprise.
“The defeat wasn’t by luck, we didn’t perform well in attack. We were surprised by two set-piece actions, that was the difference in the game.
“They started very aggressively and surprised us with the first goal because we were waiting for a cross. They surprised us but we couldn’t surprise them.”
Birmingham were on top from the off and Hannibal opened the scoring with his improvisation after 10 minutes.
Lukas Jutkiewicz was fouled 30 yards out and Hannibal embarrassed Button by curling into the bottom corner as the goalkeeper lined up for a cross.
Albion were always second best, with Birmingham’s determination and tempo earning a first double over the Baggies for 24 years.
Marc Albrighton had a shot deflected wide and Daryl Dike was an occasional nuisance but there was little to trouble the hosts.
Albion failed to improve after the break and Bielik made it 2-0 seven minutes into the second half when he nodded in Hannibal’s corner.
John Ruddy saved John Swift’s drive but Blues eased to victory to move 10 points clear of the bottom three – and briefly ease tensions after pre-game protests against owners Birmingham Sports Holdings.
Boss John Eustace said: “I’m so proud of the group, it’s a difficult day with the protests and it shows the character of the group.
“We were favourites for relegation at the start of the season, we have a group who are very honest and proud to play for the club and who will fight and scrap for each other.
“It’s an excellent performance, we were very aggressive and you can see the togetherness there.
“When you get knocked and people doubt you and it’s all doom and gloom, if you do things properly and look at the bigger picture the players can understand.”
