Despite winning the Premier League title last season, Manchester City still has a sense of inferiority heading into Sunday’s derby with United.

City has emerged as a force over the last two years, with more than a $US1 billion ($A958.18 million) of investment leading to its first English league title in 44 years. But United remains the clear global power after winning a dozen Premier League titles since 1993.

And, heading into the first Manchester derby of the season on Sunday, United holds a three-point lead over second-place City.

“They are better than us at this moment,” City manager Roberto Mancini said on Friday. “We have only been here for two years. They are used to playing these games in the title race for 20 years. They have won everything for 15 years.

“You can’t change this in two or three years. You need more time.”

City, though, beat United twice in the league last season and claimed the title on goal difference, helped by a huge victory at Old Trafford.

“The derbies had a big impact (last season), particularly that 6-1 defeat, on goal difference,” United manager Alex Ferguson said. “That’s what cost us.”

Neither United nor City has really impressed this season, and they have established themselves as frontrunners in part due to Chelsea’s slump.

City is unbeaten after 15 games but has drawn six of those. United has been relying on its powers of recovery to sit at the top with seven of its 12 wins recovered after falling behind first.

“I am sure City will be working on set pieces because I think we’ve lost something like 10 goals from set plays this year, which is a lot,” Ferguson said. “We’re hoping to find a solution and we’re hoping a solution makes a difference.”

The Manchester derby has established itself as the biggest fixture in the English football calendar, displacing United’s matches with Liverpool.

“Liverpool and United games over the last 25 years have been unbelievable,” Ferguson said. “They’ve always been the most important games. It’s shifted because at this moment Liverpool aren’t challenging for the league like City are.

“City are our biggest threat and we’re their biggest threat, so that’s changed. Their fortunes changed the minute Sheikh Mansour (bin Zayed bin Sultan Al Nahyan) took over (in 2008) … we have to accept their challenge like we did when Chelsea came along.”