A dramatic day in the Premier League saw Manchester United leapfrog neighbours City into first place for the first time since October.
City lost at Swansea City courtesy of a Luke Moore winner in the last 10 minutes whilst United vanquished West Bromwich Albion 2-0 at Old Trafford thanks to a Wayne Rooney double.
Micah Richards had an equaliser disallowed at the Liberty Stadium in the 89th minute by official Sian Massey for offside, consigning the Citizens to their fourth league defeat of the season.
United led West Brom 1-0 at half-time thanks to Rooney diverting Javier Hernandez's shot past ex-Reds stopper Ben Foster in the 35th minute after a sustained spell of pressure.
Gallery of the top two's clashes:
The Baggies missed a good early chance through Keith Andrews, who stretched to make Liam Ridgewell's cross but poked just wide, before David de Gea was called on to make an excellent stop at 0-0 after Peter Odemwingie deflected Andrews' free kick.
Martin Olsson picked up two yellow cards in the second half to give United a man extra before Andrews' lazy tug on Ashley Young saw Lee Probert award a penalty, which Rooney dispatched.
In Wales meanwhile, Scott Sinclair had a feeble penalty saved by City 'keeper Joe Hart after he was adjudged to have brought down Wayne Routledge in a frantic first-half.
In a breathless game which was inexplicably goalless until the dying embers, Moore headed in Routledge's cross with just seven minutes remaining before the Swans resisted a late onslaught from their visitors.