United's French left-back Patrice Evra has told reporters in his home country that Liverpool's Luis Suarez made continued racial slurs towards him, claims the FA are now looking into.
The FA has confirmed that referee Andre Mariner was made aware of the allegation at the end of the game before reporting the incident.
"There are cameras, you can see him say a certain word to me at least 10 times. No place for that in 2011."
"The referee is aware of what was said."
Liverpool, meanwhile, are denying the claims, a club spokesman telling the Daily Mail: "The first we knew about these allegations was 20 minutes after the final whistle when the manager was asked to go into the referee’s office and told about them.
"The first thing we did, as you would expect, is ask the player and he has categorically denied using any language of that nature."