Rio Ferdinand is adamant Manchester United have the strongest squad in the Premier League, despite Manchester City's continued spending in the transfer window.

Having completed the signing of Edin Dzeko for a fee in the region of 27 million already this month, Roberto Mancini is still exploring ways he can add to his options at the City of Manchester Stadium. While his opposite number at Old Trafford, Sir Alex Ferguson, has been quiet so far this January, Ferdinand has no doubts United are still the team to beat, and is unconcerned by the activity of the club's local enemy.

"I'm happy with the players we've got, I'm sure the manager is too," Ferdinand said. "If he sees fit to add to it, I stand by whatever decision he makes. But I don't see a problem with the depth of our squad. When everyone's fit, we've got the best in the league."

United currently sit top of the Premier League on goal difference from their cross-city rivals, having not been beaten in their 21 games to date.