Edwards believes Ferguson still has what it takes to - despite their recent 6-1 derby defeat at Old Trafford.
"Don't forget that we've had challenges in the past," Edwards told the Mirror.
"Newcastle, under Sir John Hall, had a bit of a throw at it and almost won the league, while Blackburn actually won it under Jack Walker in 1995.
"Now City have come along and you can't minimise the threat. They are a huge challenge. Abramovich is a multi-billionaire and Abu Dhabi are also a huge threat.
"It's a big challenge because, if you have enough money or unlimited resources, you will get success eventually because money buys the best players.
"You've to get your manager right, but if you have the right man in charge and can afford the best players, you're going to win things eventually."