Villa's visit is key to Mancini at the start of a massive week with a must-win Champions League tie against Villarreal and then the Manchester derby next Sunday.
He said: "It is very important that we start back in the Premier League with a victory.
"But it will be hard because Aston Villa are a very good team. They haven't lost a game yet. We will need to play very well.
"Alex McLeish is a good manager. He has the experience in the Premier League and a good team with good players. They have started the season very well."