A winner from Carlos Tevez gave the holders three points at Old Trafford, but Fergie believes the fans should have done better especially after last weekend's defeat at West Ham.

"The atmosphere was not very good, it was like a funeral out there and we needed the crowd to lift us a bit. We needed that today," Ferguson told Sky Sports.

"It was the quietest I have heard here for some time and the atmosphere today did not help us.

"Sometimes we need them to get behind us. They can help produce the right performance but we did not get that today."

Not the Best

Apart from the fans' behavior, the Scotsman also admitted that his players could have had a better game against the Blues, who were close to causing an upset near the end.

"We were very careless with our finishing; we need to be doing better," added the United boss.

"The last 15 minutes was all Birmingham and we could only have blamed ourselves if we had conceded. We could have been embarrassed."

United were without first-choice goalkeeper Edwin Van der Sar (groin) and striker Wayne Rooney (illness) during the narrow win.