Veteran Scottish striker Kenny Miller opened the scoring for the hosts in the first half, before Anthony Gerrard doubled Cardiff’s lead early in the second period.
The defeat leaves Steve Kean with a disgruntled and frustrated Lancashire fan-base to deal with, and attention will now turn to picking up points in the Premier League to avoid being bottom at Christmas.
The Scottish coach was clearly disappointed with the result, but admitted his team selection was effected by the upcoming league clash with Swansea on Saturday.
“The side we put out tonight was with one eye on Swansea at the weekend,” he told Sky Sports.
“I felt that we started the game very well. I felt the first 15 minutes we had the best two opportunities and then when Cardiff managed to score they had a good period
“I took the decision to make five changes and on top of that we have (Christopher) Samba and (Martin) Olsson back so we will have seven faces fresh for Swansea.
“Saturday’s a massive game for us and a game we need three points from; obviously I’ve got one eye on it.
“We’ve some very good games at home coming up, teams that are within touching distance of us and these are our cup finals, the league games coming up are all cup finals,” he concluded.
Cardiff supporters meanwhile will be dreaming of glory, as they enter the semi finals draw for the cup, and are joined in the hat by Liverpool, Manchester City and either Manchester United or Crystal Palace.
By Gareth McKnight