Having lead early on in the game through Nicky Butt's first ever goal for the club, some poor defending allowed Manchester City to leave St Andrew's with maximum points on Saturday evening.
"It's always disappointing to lose at home, thats for sure," Bruce said after the 2-1 defeat..
"We had a glorious start - we couldn't have asked for anything better - but overall I didn't think we defended well enough.
"Vassell and Cole caused us all sorts of problems and we basically didn't deal with that.
"We've gone 1-0 up in the game and at times we were still playing with two out-and-out wingers, and getting seven people in the oppositions box. I thought we were undisciplined.
"We've had some good chances in the game and one or two good penalty shouts - I thought the one on Nicky Butt was a stone-wall penalty.
"But, I think if we had defended better as a team then we would have done better than what we did."