Mancini warned the best is yet to come from his City players, who face Reading at home on Saturday and return to the North East on Boxing Day seeking revenge at Sunderland for last season's New Year's Day defeat.
Mancini said: "I think if we put our minds on the job we can do very well, like we did at Newcastle today. But if we think we can play with only one foot, it is difficult.
"We felt it would be really difficult here because when you play against Newcastle after a defeat against United it's clear that it will be tough. It was very important only to play like we did in the second half against United - and we did this. Sergio and Carlos play very well together and this is very important but we have also Edin (Dzeko) and Mario.
"When he came on, Edin did very well and to win at Newcastle you need to play very well with your whole team.
"It's important they always play at 100 per cent with a good attitude."