Substitute Didier Drogba scored a controversial winner as Chelsea leapfrogged Manchester United to seize pole position in the Barclays Premier League title race with a 2-1 win.
Clearly offside as he drove home Chelsea's second 12 minutes from time, the mistake seemed of minimal interest at the time given the Blues were already in front through Joe Cole and had controlled the contest for long periods.
But when Federico Macheda responded for United almost immediately, Chelsea were left clinging on to a winning goal Sir Alex Ferguson will claim should never have been allowed.
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