"We were playing a team today who were organised, disciplined and experienced," Malky Mackay said.
"The way they set up, every time we had it those two central midfielders sat straight in in front of the back four.
"We knew they were going to be a tough nut to crack today, but we spoke at half-time about being patient, that if we keep shifting it and playing the way we can play chances would come and they did.
"I'm delighted with the clean sheet - three in a week - so we're really building confidence as far as that's concerned. And I was delighted to see the game out as well."
Mackay expressed his pleasure at the speed with which his new-look side has gelled.
The victory propelled Cardiff back into third in the Championship, despite welcoming 12 new players during the summer, and Mackay said he felt the Bluebirds have progressed as a unit quicker than he had hoped they would.
"From the start of the season I thought we could fast-track them in terms of knowing how each other play," he said.
"You've got to work hard on the training pitch to make it work quickly and to that extent we've clicked a little quicker than I thought we would as a team."
Birmingham boss Chris Hughton insisted the dismissal of Davies was harsh, pointing to the incident as the moment that the match swung in Cardiff's favour.
"My first reaction was to look at Curtis and Curtis jumped up straight away from the incident and didn't feel anything because he touched the ball," he said.
"I think there was enough doubt on the incident that you don't give a red card.
"Stephen Caldwell was in close proximity and I can't sit here and say there's definitely no incident, but there's enough doubt that you can't give a red card.
"The game very much hinged on two instances. Of course the sending off, but also I thought in the first half we coped very well with a very real threat in Miller and I was confident we could cope with it in the second half again.
"The sending-off does change things but we can't make the kind of mistakes that we made and expect not to get punished."
Source: FOOTYMAD
