Blues had the lions-share of possesion against Steve McClaren's side but missed three good opportunites to score before Mark Viduka's goal settled the game just before half time.
"We played particularly well in the first half and they never really caused us any problems but it's a simple scenario, if you come away and play well like that you must take your chances," a disappointed Bruce said after the 1-0 defeat.
"We've had 3 or 4 opportunities and when you get to this level and goalscoring opportunities like that come along you have to take one of them.
"Unfortunately as a team, not just the strikers, the whole team has to contribute into scoring a goal. That's been our biggest problem all season.
"We didn't deserve to lose today, for me we were by far the better team.
"If we keep playing like that and stay positive I'm sure we'll get out of trouble. We didn't look like a team who are in the bottom three today."