Keane came from behind him and nonchalantly stroked into an empty net to give Spurs a 1-0 lead.
"Poor Andy's waited to play in the Premiership again, so for that to happen was very cruel," said Bruce.
"He put the ball down, as keepers do because they'd rather kick it off the floor than out of their hands. I saw Keane behind Andy but couldn't shout loud enough to tell him he was there.
However, Bruce was pleased with the way Blues came back and is convinced that with more performances like this one they will remain above the bottom three and stay in the Premiership.
"Sometimes football kicks you where it hurts and that was one of those games today," he said.
"We were the better team, created the better chances and probably played the better football. We had four clear-cut chances in the first 20 minutes but you've got to take your chances.
"We made two mistakes and Andy's after just five minutes summed up our day.
"Then they had a kick down the middle late on. It bounced up and Poyet hit it into the top corner.
"Results have gone against us today so it's a pretty miserable weekend. But four of our six games are at home and we'll be okay if we maintain that performance level and the spirit we showed today stays with us."
