Chelsea has lodged a complaint with the The Football Association (FA) alleging that referee Mark Clattenburg used inappropriate language directed at John Mikel Obi during the "bad-tempered" match on Sunday which marked the Blues' first in the Barclays Premier League this season.
The Sunday's match, which Manchester United defeated Chelsea 3-2, was marred by controversial winning goal and referee Mark Clattenburg's alleged racial comment on The Blues' player. Branislav Ivanovic and Fernando Torres were also shown red cards just a few minutes into the second half.
Chelsea on Wednesday said in a statement that they decided to loadge a formal complaint after a thorough investigation into the matter.
"Board members began establishing the details of the allegations, speaking to all relevant players and staff. After those initial interviews it was clear that the matter had to be reported. The correct protocol for doing so was to report the incidents to the match delegate, and the club took immediate steps to inform him as soon as he was available. It was not a decision the club took lightly," said the statement.
"Since reporting the matter to the delegate, the club and outside legal counsel have conducted further investigations. Having completed that process we have now followed the correct protocol and lodged a formal complaint with The FA regarding John Mikel Obi. There was no sufficient evidence to support a second claim to The FA with regard to the alleged verbal abuse of another first team player," it added.
The club had earlier lodged a complaint to the Premier League match delegate for the use of "inappropriate language" on two of their players by referee Clattenburg. One of the comments, believed to be directed at John Obi Mikel, is allegedly racial in nature.
The allegation on the referee came at a time when English football is being hit by racial abuses, with Luis Suarez and John Terry being banned for several matches by the Football Association (FA) after they were found guilty of racially abusing other players.