West Ham boss Alan Curbishley was delighted with the response of his players after being beaten by Manchester City and with sharper finishing they would have ran out more comfortable winners against Birmingham.
He said: "It was such a flat game against Manchester City. There was lots of work that had to be done in training this week.
"I think both sides found it tricky in the first half with the gale-force winds and driving rain but we were strong after the break.
"We are a pacy side who have got the ability to break and the confidence came back when we got going.
"As for the penalty, it is one of those where if the keeper comes out he has got to get the ball. I don't think he did. It was one of those where sometimes you get a penalty and sometimes you don't. We were just delighted to get it."
Blues manager Steve Bruce felt incensed for the second time in 72 hours after believing his keeper Colin Doyle had also been fouled when Sunderland scored their last-gasp equaliser in Wednesday's 2-2 draw.
He said: "I didn't intend to come out here and bleat and West Ham were the better side.
"But in my view it wasn't a penalty against Colin. It was an experienced player (Bellamy) knowing exactly what he was doing and there was a bit of inexperience from my keeper.
"He has made a genuine attempt to play the ball and any contact at all was minimal. We have now had two decisions go against us in three games and they have cost us dearly.
"I did wonder if it was a case of the big club versus little club syndrome. The big clubs always do seem to get the decisions against the small clubs and we've been on the end of two howlers in my opinion.
"I also felt we paid the penalty of three games in six days whereas West Ham hadn't played since last weekend.