He feels Newcastle, following the takeover by Mike Ashley, can match his former club and has urged caution on the part of City fans.
'It is important they don't get too carried away with a couple of results,' he added.
'Hopefully we'll get the kind of investment they got at Manchester City and get a similar result.
'I think Newcastle can be as big as they want to be. No disrespect to City but in Manchester, Manchester United will always be top dog. As much as they want to believe it, it is not going to be.
'The big thing about Newcastle is there is only Newcastle in Newcastle. Newcastle could be a big side and turn it from a big four into a big five