In the second half Blues carried on in the same vein but succumbed to Fulham's smash and grab approach when Mark Pembridge scored the only goal of the game with their first real effort on goal in the 76th minute to send the West Londoners into the 4th round.
"We're shocked that we lost that game. We didn't deserve to lose considering the chances we've created," Bruce said after the 1-0 defeat at St Andrew's.
"Mark Crossley has had one of those nights he'll remeber for a long time - he was terrific.
"Its just not going for us at the minute but if we keep playing like that then I'm sure our luck will change.
"We've played very, very well, especially first half and didn't get the result we deserved.
"We've just got to keep plugging away."