Mancini said: "We deserved to win this game. We had a lot of chances, we played well, but we didn't score. This is our problem, we don't score, we don't score enough goals to win the game."
"Last year, we scored one, two, three goals every game. Now when we have chances, we are too soft and this is not good.
"We are too soft in attack, too soft when we have chances, too soft when we shoot. Sometimes we don't shoot, we want to have one touch more. This is not good."
Opposite number Martin O'Neill, however, was not in the slightest bit interested in Mancini's view.
He said: "Honestly, I am really not particularly bothered, I am genuinely not bothered about what Roberto Mancini would say about the team. I have seen it before with other managers. I'm not bothered. I thought we were terrific today."
Asked if the performance was Sunderland's best of the season, O'Neill said: "Considering the opposition, I would have to say yes.
"We gained a bit of confidence form winning against Southampton and took that into the game, but we knew there would be times when we would have to play without the ball and we would have to defend strongly, and we did both of those very well.
"And yet we were able to carve out some great chances in the game."