Manchester United legend Steve Coppell has hailed the quality of Sir Alex Ferguson's squad but remains wary of City's recent emergence as a force in the Premier League.
Ferguson's United have made an impressive start to the 2011-12 season with the club currently at the summit of the Premier League table after claiming five wins from as many games and scoring 21 goals in the process.
City, meanwhile, who have benefited from heavy financial investment in recent years, look genuine contenders for the title this campaign, with the club placed second at present after their 100% record came to an end with a draw at Fulham last weekend.
Coppell, who made over 300 appearances for United as a player and later spent a brief time as boss of City, said: "You look at the squad Alex has developed and it just looks to be exceptional.
"I've yet to see the confrontation with Manchester City but, in terms of the depth of squad United have, I can't see them falling. Alex called them the noisy neighbours. But now they're beginning to walk the walk.
"All of a sudden, it's a head-on battle across the city. It'll be fascinating to see the first derby this year to see who comes on top."
Coppell also reserved particular praise for Ferguson, who will see his United side lock horns with City in the league on October 23 ahead of celebrating a quarter of a century in charge of the Red Devils.
"His drive, even now, has been incredible," Coppell said, speaking at the launch of Manchester United '19', which chronicles each of the club's record-breaking 19 league titles.
"I think he gets reinvigorated by forever chopping and changing the team, bringing new elements to the side. It's easy for a manager to become complacent, but he never does. The joy for every goal they score is apparent when you watch him on the sideline, the pain of every goal conceded."
• '19' is published by Empire Publications and an be purchased at www.empire-uk.com