Cardiff boss Malky Mackay heaped praise on his "professional" Bluebirds after a 1-0 win at Birmingham.
The victory, courtesy of Joe Mason's fifth goal of the season, opened up a seven-point lead at the top of the Championship.
Mackay, who had to make five changes to his injury and illness-hit side, was delighted with the grit shown by his team.
"It was a tough team we played and we knew we had to battle and fight for everything we got," he said.
"We are now seven points clear at the top but it is just about making sure about the game you are in and keep chalking them off.
"It has been a tough period but we have the momentum and consistency which I am delighted about.
"We were without Andrew Taylor who fell ill on the morning of the game. Simon Lappin came in and did a good job. He showed why he has played at the top level.
"It was a professional-like performance by the team. You have got to be in this division as you have to respect for the opposition because you are not going to score bags of goals.
"To come away with the 10th clean sheet for the season was outstanding and we were very comfortable in the second half."