This is the first reported case of a referee allegedly racially abusing a footballer. Previous cases have been between players or fans.
But Monday, the English FA who are custodians of the Beautiful Game decided to launch an investigation into the matter to prevent it from further creating tension in the Premiership that is gradually becoming notorious for racial abuses.
An FA statement posted on the FA's website read: "The FA has begun an investigation relating to allegations made following Sunday's fixture at Stamford Bridge between Chelsea and Manchester United. The FA will make no further comment at this time."
Chelsea made a complaint to the Premier League after Mikel stormed into the referee's room to demand an apology after claiming referee Mark Clattenburg made a racist slur when he booked the midfielder in the 76th minute.
One of Chelsea's Spanish stars is also involved after players claim they heard Clattenburg refer to him as 'a Spanish t**t'. Spaniards Fernando Torres, Juan Mata and Cesar Azpilicueta all played against United.
It has also emerged that Clattenburg has been stood down from this weekend's Premier League action, according to The Daily Mail.
The FA will now request all footage from Sky Sports from the game.
While not all are recorded, they should help confirm whether Clattenburg made an inappropriate or racially aggravated comment.
However, these discussions are not recorded - meaning it could come down to one man's word against another, like in the John Terry and Anton Ferdinand race row.
Chelsea, United and anti-racism group Kick It Out all refused to comment on the unfolding story Monday morning.
However, 'The Blues' did confirm they had decided against holding a press conference Tuesday to preview Wednesday night's Capital One Cup clash with United. Lee Mason is the referee for that meeting.
Former England Captain, John Terry was involved in a spat with Antone Ferdinand that led to his ban for four games. Last season, Luis Suarez and Patrice Evra similarly engaged in a war of word over racial abuse. Suarez was banned for 10 matches in addition to a hefty fine.
It was the handling of Terry's affair that led Antone's brother, Rio Ferdinand to refuse to wear the shirts denouncing racism in football recently.