Chelsea's Juan Mata was not aware of any comments referee Mark Clattenburg is alleged to have directed at him during Sunday's defeat to Manchester United, according to his Spanish team-mate Oriol Romeu.
The European champions and Premier League leaders lodged an official complaint against Clattenburg following the weekend's controversial clash at Stamford Bridge by what they claim were racist and xenophobic comments made by the official towards two of their players, Mata and John Obi Mikel.
Chelsea's complaint is that Mikel was the victim of a racist comment, while Spain midfielder Mata was allegedly called a "Spanish t**t" by Clattenburg.
The FA announced on Monday that it would be conducting an official investigation, while the Metropolitan Police also confirmed they have received a complaint.
The Professional Game Match Officials organisation has confirmed that Clattenburg will not officiate a match this weekend stating, "that with any football match the focus should not be on the officials but on the players and the game itself"
But Romeu, one of four Spanish players in the Chelsea squad along with Mata, Fernando Torres and Cesar Azpilicueta, said that neither he nor any of his compatriots heard Clattenburg say anything untoward.
The Sun quoted the former Barcelona midfielder as telling Spanish radio station Cadena Cope: "Neither Juan nor Fernando told me they heard it because from what I have understood they didn't hear anything.
"It was someone else who heard it, but not directly at them. It was another player who heard it and that is what they told me.
"I didn't hear anything as I left quickly to go home but after talking to Juan he told me there was some problem and he had to stay.
"I only know Chelsea made a complaint and I think there could really be a problem if what Chelsea players say happened really happened."
Oriol, who was an unused substitute for the match in which Chelsea had Torres and Branislav Ivanovic sent off and lost to a controversial goal from Javier Hernandez, added: "If there was really a racist comment or something said against a Spanish player this will be serious.
"We know in this country people are very vigilant about these issues."