LONDON: Chelsea have followed up their 3-2 home defeat by Manchester United on Sunday with a formal complaint that referee Mark Clattenburg used “inappropriate language” towards two of their players.

Media reports claimed that a racist element was concerned in the complaint which involved midfielder John Mikel Obi.

A Chelsea spokesman said: “We have lodged a complaint to the Premier League match delegate. The match delegate will pass the complaint to the Football Association.”

Referees’ organisation Professional Game Match Officials (PGMO) later issued a statement which read: “PGMO is aware of the allegations and they are being treated with the utmost seriousness. Mark will co-operate fully and welcomes the opportunity for the facts to be established.”

All four officials – the referee, his two assistants and the fourth official – wear microphones and ear pieces that allow them to hear what each other is saying throughout the match, although it is not recorded.

Premier leaders Chelsea lost their unbeaten record after Javier Hernandez struck a controversial winner 15 minutes from time.

Chelsea’s Branislav Ivanovic and Fernando Torres were shown red cards in the space of five minutes, with the latter’s second yellow card for diving disputed by Chelsea. Torres was sent off in the 68th minute after falling under a challenge from defender Jonny Evans.

Chelsea also felt aggrieved that Hernandez’s winner was allowed to stand, as television replays suggested he was marginally offside before converting Rafael Da Silva’s cross.

Immediately after the game Chelsea manager Roberto Di Matteo said: “It is a shame a game like this had to be decided in that manner by officials. Surely when the referee watches it he will realise he has made big mistakes.”

Durham-based Clattenburg, 37, is a FIFA referee who controlled last season’s League Cup final in February and the Olympic final between Brazil and Mexico at Wembley in August.

In 2009, he was suspended over allegations about his business dealings but Clattenburg appealed and returned to officiating after an eight-month ban.

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