The Sun on Sunday claims Guardiola will opt for City over Chelsea because he sees the Abu Dhabi-owned side as being the more likely to challenge for European honours despite the London side having won the Champions League last season.
Mancini - who has won an FA Cup and the Prmeier League titles in his time at the club - is set to pay for his failure to guide the expensively-assembled side into the Champions League knockout stages on two occasions.
"It is 100 per cent certain that Guardiola is going to City this summer," a high level source in Spanish football told the paper.
"And when I say 100 per cent I don't mean 99 per cent, I mean 100 per cent!"
According to the paper, Guardiola will become the highest-paid manager in England on £10 million pounds (12,085,500 euros, $16.1million US) a year after tax.
Inter outclass Parma, up to third
Milan: Inter Milan outclassed league new boys Pescara 2-0 at the San Siro Saturday to move two places up to third and close the gap to leaders Juventus to six points. Juventus are away to Parma on Sunday but will be expected to pick up three points against a side they beat 2-0 at home on the opening day of the season in August. Lazio remain second, five points shy of Juventus.