Uefa will probe Anderlecht substitute Nenad Jestrovic for alleged racial abuse of Liverpool's Mohamed Sissoko in Tuesday's Champions League tie.
Jestrovic claimed Sissoko swore at him but it was the Serbian's comments which saw him immediately shown the red card by referee Kim Milton Nielsen.
Nielsen's report is now being studied by Uefa, which confirmed it will begin an inquiry into the alleged "insult".
Jestrovic denies racial abuse saying "I can't understand why I was sent off."
These things should not be said, but I do not intend to punish my player further
Anderlecht coach Frank Vercauteren
The Anderlecht striker, who had only been on the pitch for five minutes, added, "I approached the referee after the game and he said it was for an obscenity."
Anderlecht coach Frank Vercauteren said he could not condone Jestrovic if it was proven he had racially abused Sissoko.
But he would not take any further action against his player until he knew the full details of Nielsen's report.
"If it was racial abuse, I cannot condone that," said Vercauteren.
"The other player should also have been sent off as well. He said something similar.
"These things should not be said, but I do not intend to punish my player further."
Liverpool boss Rafael Benitez said: "I have not spoken to Sissoko about what happened so I do not know what was said."
Uefa will now begin their inquiry which could take up to 15 days to reach a conclusion.