Mancini has come in for criticism from some City fans for his tactics and team selections.
"He's very clear in what he brings across to the players, always positive," said Kompany.
"Ultimately, he gives tactical advice because we need to know where to stand. We didn't do too well [against Sunderland] but we need to play in a way we can dismantle the other team and usually it works well.
"With what we have shown at home for the past year or more, we are disappointed."