The former Arsenal midfielder expects this season's title race to be open.
"The league is more exciting now than ever and there are six teams that can win it," Vieira told BBC Sport.
"City are now as good as United, Arsenal and Chelsea and we should not be afraid to say we can win the title."
"It will not be easy but I think people can count on City being there right until the end. If you look at the quality of the team and how City have improved over the last few years, we can now challenge to win the Premier League," Vieira added.
"We are improving a lot and some fantastic players have joined us this summer and we are strong enough to compete at the top."