Peter Schmeichel now sees Manchester City as a "bigger club" than rivals United, based on recent form.

The teams lock horns on Sunday in the first Manchester derby of the season.

In his eight years at Old Trafford, Schmeichel was never on the losing side against City.

The Danish goalkeeper won five Premier League trophies between 1991 and 1999 while the Light Blues fell to the third tier of English football.

But the 50-year-old thinks the balance of power has well and truly shifted in City's favour.

"In my first couple of years [at United] I didn't understand [the rivalry with City]. Liverpool and Leeds were much bigger," Schmeichel said.

"Now it's different. City are the champions, they had their second Premier League win last season and maybe at the moment they are a bigger club than United in terms of results - so the significance has changed."

Schmeichel spent one season at City before retiring and his son Kasper came through the youth system at the club before leaving five years ago.

The Champions League winner is still very much a United fan, though, and admits playing against Sir Alex Ferguson's team in City blue was a "very weird" experience.

Schmeichel is worried by the inconsistency shown by the team since Ferguson retired.

United had hoped Louis van Gaal would steady the ship following David Moyes' woeful 10-month spell at the helm, but the Dutchman has only won three games and his team sit eighth in the table with nearly a quarter of the campaign gone.

Going into Sunday's tie at the Etihad Stadium, Schmeichel spoke of his fears over United's up-and-down form, which has seen them earn a creditable draw with Chelsea but lose to Leicester and Swansea.

"It [the derby] is a tricky one for United because of their inconsistency," he said. "They have defended badly then well, scored a lot of goals and then not a lot of goals.

"The Leicester game was the best example. They went 1-0 up, 2-0 up then 3-1 up and lost 5-3. That's unheard of.

"It's not Manchester United or the way they want to be. We don't know what we will get on Sunday."

Although the arrivals of Angel di Maria and Radamel Falcao lifted spirits at Old Trafford, Schmeichel is concerned about United's poor performances at the back. So far this season they have conceded 13 goals.

Unless Van Gaal adds more steel to his back four in January, Schmeichel thinks the United boss can kiss goodbye to any hopes he has of qualifying for the Champions League.

"I think it is a work in progress for Louis van Gaal," said Schmeichel, who played 398 times for United.

"His signings were good this summer, they lifted the fans and brought hope, enthusiasm and belief it can be done, but we need to tighten up in defence.

"Conceding that many goals is never going to win you anything.

"We have to tighten up at the back and then they will finish in the top four."