City were on the back foot for most of 2nd half and offered little of the superb football that saw them take a two goal lead early on.
Kimbo and Campbell had put Cardiff firmly in control but Brentford pulled one back just before half time before going onto win the game in the second half.
There were lots of 2nd half subs but it was concerning to be over run by Brentford when we will have much sterner tests to come.
Next up City face Chievo at CC on Saturday.