Having earlier this month become the first side to win at Manchester City this season, the Portuguese insisted his side were not serious contenders for the Barclays Premier League title.
Mourinho called his side a ''little horse'' in comparison to fellow title challengers Arsenal and City, whose manager Manuel Pellegrini quickly hit back at such talk.
The man he succeeded at the Etihad Stadium echoed those thoughts on Tuesday, with Mancini, now manager of Galatasaray, insisting Chelsea's class and experience makes his team huge underdogs for the last-16 clash.
''It's a young team, like ours,'' the Italian said with a smile. ''We are young.
''I think that Chelsea are on top of the Premier League because they are a top team.
''They have really good players - these players who can change the game at any moment.
''They have fantastic players who are used to playing games like this. I think they have an 80 per cent chance of going through.''
Mancini believes a positive result is required on Wednesday if the Turkish champions are to stand any chance of progressing to the quarter-finals.
Galatasaray's attack is expected to be their biggest strength in the last-16 tie, with two men Mourinho knows well key to that.
Wesley Sneijder won the Champions League under the Portuguese at Inter Milan, while the match will be Didier Drogba's first against Chelsea since ending his time with the club as a European champion.
''Didier was an important man, an important player for Chelsea,'' Mancini said.
''Wesley won under Mourinho a Champions League.
''They have a good relationship with him, but tomorrow, for 90 minutes, I think they will be enemies.
''Ninety minutes, afterwards, they can go and have a dinner together. But for 90 minutes they should not play 100 per cent, but more. We need Didier and Wesley to play very, very well tomorrow.''
Mourinho was left to insist his relationship with striker Samuel Eto'o has been unaffected by footage showing him questioning the Chelsea striker's age.
Preparations for Wednesday night's match have been somewhat overshadowed by French television station Canal Plus broadcasting video of the Portuguese making inflammatory comments to a businessman at a recent sponsor's event.
The recording, aired on Monday, shows Mourinho commenting on Chelsea's lack of depth up front and questioning the age of Cameroon forward Eto'o.
Not knowing he was being filmed, the Blues manager was recorded saying: ''The problem with Chelsea is I lack a striker. He (Eto'o) is 32 years old, maybe 35, who knows?''
Mourinho was apoplectic about the remarks being broadcast, telling journalists they ''should be embarrassed'' by what has happened.
''I'm not defending what I'm saying, I'm attacking something that is, I think, fundamental in your professional area,'' he said.
''That person showed exactly what he is, or what he doesn't know about the job.
''From my perspective, the comment is obviously not a good one, and obviously not something I would do in a serious way, something I would not do an official way in an interview.
''First of all, because I don't make fun. Secondly, because if there are managers in the world who really defend their players, I'm obviously one of them.
''And third because Samuel Eto'o is Samuel Eto'o. He's four times a Champions League winner: people think three times, but one in Real Madrid, two in Barcelona and one with Inter.
''It was with him that I had the best ever season of my career. He's one of the few players who is working with me at a second different club, and a manager never does that if he doesn't like the player or the person.
''He has no reason to be upset because also, he told a few years ago, that Mourinho is the only manager in the world who I would never play for, and after one year he was playing with me at Inter and now here.
''There is no story, there is no story. I repeat: it was a funny conversation between me and somebody who doesn't belong to the football world.
''We were laughing as everybody was saying. I really think it's a disgrace that someone is taping and recording a private conversation when, obviously, we don't know.''
That was the second question Mourinho had fielded on the subject and he snapped when a third was asked about whether the relationship with his strikers have been damaged by the remarks.
''If you want to speak about the game, I'm ready,'' he said.
''If you want to keep speaking about some non-ethical journalist, I've had enough.''