Former Manchester City boss Peter Reid believes the current team can beat Manchester United to the Premier League title after thrashing their rivals 6-1.
City's win extended their lead at the top of the table to five points and Reid believes the strength of the City squad has overtaken United's.
"You don't win anything in October but they are hard to beat and they have strength in depth," said Reid.
But ex-United midfielder Lee Sharpe said there had not been a power shift.
He told BBC Sport: "Manchester United are still vastly experienced when it comes to winning leagues and winning games.
"It's maybe a wake-up call to work on a few things, but they will come back from this and they will still be challenging for the league.
"When it comes to the last six games of the season when the pressure really starts to mount that is when United have the experience of being in that position before whereas City haven't, so nothing is won or lost just yet, it was just a bit of a shock result."
Manchester City have not won the top-flight title since 1968, during which time Manchester United have won 12 league titles.
But Sunday's defeat was the heaviest suffered by United manager Sir Alex Ferguson and the worst loss at Old Trafford since 1955.
Reid, who managed City between 1990 and 1993, believes the manner in which City won the game showed there is an added swagger to the side.
"David Silva is possibly the best player in the Premier League this year, that has helped them," he told BBC Sport. "Samir Nasri and Sergio Aguero have come in and they are attacking-minded players.
"There is a belief and a confidence from the manager [Roberto Mancini] and I think the players have got that as well.
"There was a real confidence about the way he went about it at Old Trafford, but don't write off the red half of Manchester.
"They've been there before and, knowing Sir Alex Ferguson as I do, it wouldn't surprise me if he went into the transfer market in January and bought a couple of midfield players but that result for City will be massive for their confidence."
Sharpe, who played for United between 1988 and 1996, agrees that City have a chance to win the Premier League this season but states that experience favours Chelsea and his former club.
But he thinks Ferguson's side, which have conceded the most number of shots in the Premier League this season, need to be better organised and have more consistency in defence.
"United need a bit of organisation and a bit of leadership," he added. "Rio Ferdinand has been out for quite long periods, Nemanja Vidic was not playing on Sunday.
"I know Wayne Rooney is there with a bit of experience who can grab people by the scruff of the neck, but they maybe need a midfielder who can be a leader and tighten things up when things are going bad for them during the game. A bit of consistency in the back four would also help.
"Newcastle have conceded six goals and they have had the same back four and the same keeper in every game and United have not done that."