Chelsea has made a formal complaint about the language, reportedly racial, allegedly used by referee Mark Clattenburg to two of its players during the controversial 3-2 home defeat to Manchester United.

The dramatic development, which came after a stormy top of the table clash at Stamford Bridge on Sunday, will add fire to Wednesday evening, when the two sides meet again in London in the League Cup.

"We have lodged a complaint to the Premier League match delegate with regard to inappropriate language used by the referee and directed at two of our players in two separate incidents during today's match," said a Chelsea statement.