United were held to a 4-4 home draw by Everton while City took advantage by winning 2-0 at Wolves to doom the Black Country side to relegation. But Mancini remains adamant the title is "not in our hands" even though City have a superior goal difference.
He said: "Is it a good day? Not really. We won a difficult game. Wolves are relegated. I don't think they deserve to be there. I'm very sorry for them. They fight for every ball. For us, we didn't play well today. Only one team can win this title. It's not in our hands. We have three points less."
He added: "You all wrote the title race was finished. Seven days ago, the race was finished. You wrote it. I congratulate Sir Alex Ferguson on a good season.
"After the derby we play Newcastle, who are fighting for the Champions League, and QPR who are fighting relegation. We can talk about the title next Monday night. It's impossible."
Interim boss Terry Connor admitted Wolves had not been good enough to stay in the top flight after a three-season tenure.
Wolves have collected only two points from 10 games since he replaced the sacked Mick McCarthy in February.
Connor said: "Ultimately over 35 games we've proved not good enough to stay in the Premier League.
"It's a really emotional, really raw day today - not just for myself, but the staff, players, supporters, everyone connected with the club. The next few days will be tough and we've got three more games to finish the season
"Wolves will always bounce back, no matter who the players or manager are. The club will bounce back."