Ferguson said: "I think we made it hard for ourselves. With all the possessions we had, the control we had, we really should have finished the opponents off. But all fairness to Middlesbrough, they kept fighting, fighting and fighting. That is what you are seeing early season. Everyone is fit, everyone is running about and using all of their energy up.
"It was an important game for them. They have started the new season very well. I thought in the main we controlled the match until the last 15 minutes."
Ferguson added: "We defended quite well, but it only takes a second to lose a goal and you are never sure. I think we did create good openings, but maybe tried to put too much icing on the cake, the extra pass, looking nice - we lacked the killer instinct and that's the part of the game we will come back on."