Souness knew Mancini as a teenager when they were team-mates at Sampdoria and believes the Italian will be better equipped for the Champions League than a year ago, particularly as he can call on Tevez this time.
He told the Mail on Sunday: "I don't regret what I said about the Tevez situation, I believe I was correct at the time and I still hold that view now. If your manager tells you to do something, like warm up from the bench, you should do it. There has to be a boss in every business.
"There is no doubt about it, though, Carlos Tevez is a top player and City would not have needed to go to the last kick of the season to win the title if what happened in Munich hadn't happened.
"What is so likeable about Tevez is that when he is on the pitch, he appears to give everything. No doubt about it, he's an asset and it'll help City this season.
"I knew Mancini as a young man, very talented but a typical No 10, he only wanted to play when he got the ball. But it doesn't particularly surprise me he's become a top manager. I gave up a long time ago working out what makes a good manager.
"I think he took a year or so to work out how to get the best out of the squad. The City team are more adventurous now.
"Sure, they will make sure they are cautious in Madrid to assess the opposition. But, in general, they score more goals now."