The Football Association will investigate an allegation of racism made by Mason Holgate after a clash with Roberto Firmino that left the Everton defender enraged.
Referee Bobby Madley included details in his report of the row that erupted towards the end of first half of the FA Cup third round tie, which Liverpool won 2-1 thanks to a dramatic late goal on his debut from £75million defender Virgil Van Dijk.
Holgate pushed Firmino into the Main Stand as the pair chased a ball. The Brazil striker reacted with fury. Television pictures appeared to show him calling Holgate 'loco' and 'filha du puto' – Portuguese for 'son of a b****'.
However, that left Holgate incensed and as he was restrained by his team-mates, television footage showed him making a serious racial allegation of Firmino. The incident was discussed by Madley and fourth official Jon Moss on the touchline.
After the game, Holgate spoke to Madley independently, as did Everton Director of Football Steve Walsh. The matter will now be in the hands of the FA, once Madley has submitted his report.
A subsequent statement from the FA read: 'The FA can confirm that referee Bobby Madley was made aware of an allegation during the Liverpool versus Everton game at Anfield and has subsequently reported this to The FA, which will now begin making enquiries into the matter.'
Everton manager Sam Allardyce refused to shed specific light on what happened but said: said: I'm telling you nothing until whatever systems are used to find out what happened.
'I'm here to talk about football. Football is my life and anything outside that has to be dealt with by the authorities.
'Even if I had or I hadn't, I wouldn't tell anyone in the press conference. That is for other areas of the football club. I have told the Director of Football to sort that out.'
There was no official comment from Everton but more discussions involving Walsh and Holgate, who deleted his Twitter account, are expected to take place Saturday.
Jurgen Klopp was similarly ambiguous when asked for his views. He had seen referee Bobby Madley and fourth official Jon Moss in discussions after Holgate and Firmino had been separated but did not know what it was about.
Klopp said: 'I only heard about it but I can't say anything about it. I haven't spoken to anyone. I misjudged the whole situation.
'I thought it was about the Holgate foul. I had information that something has happened but I don't know what happened.'
Liverpool subsequently released a statement.
A spokesperson said: 'The club and the player will fully co-operate with the relevant authorities to ensure the facts are established in a thorough manner if deemed necessary or requested.
'While that process is ongoing we will not be making any further comment.'