While Rooney admits that this year's City team does have plenty of talent and is on a great run, he doesn't think they've done it for long enough to be considered one of the top teams ever yet.
“I’m not sure they [City] are quite there. They would have to keep going and do a lot more," he told talkSPORT.
“There have been so many great teams throughout the years in the Premier League. This City team needs to win trophies and needs to do it for a longer period to be in that bracket.
“The best ever? I would go with the Man United team from 2008!”
“I don’t think they can go unbeaten,” Rooney added. “They have done incredibly well with the run they have been on, but the Premier League is so difficult, especially now with this Christmas period coming up.
“I know they have a huge squad, a great squad of players. But there are so many top teams. I think in previous years it has been two teams and you went in knowing you would win most of the other games.
“But now there are five or six other teams that can all beat each other and I’m sure in one of those games Man City will get beaten.”
Rooney's Everton were the last - and so far only this season - Premier League side not beaten by City, with the club holding out for a 1-1 draw back in August.