Reading and Leyton Orient football clubs have both condemned racist abuse received by striker Dan Agyei.
Leyton Orient's Agyei scored a penalty in Saturday's game at the SCL Stadium, which ended 1-1.
Both clubs said they were working with social media and the relevant authorities to identify those responsible and would insist on the "strongest possible punishments".
Thames Valley Police (TVP) said it was investigating.
The racist abuse appears to have been posted on X, formerly known as Twitter, after the game.
The clubs said in their statements that there was "no room for racism in football or society" and they had a "zero tolerance policy towards all forms of discrimination".
Agyei's club said it was "angered" by the abuse its player received.
A spokesperson for TVP said: "Hate crime has a significant impact on both individual victims and our communities.
"Thames Valley Police will not tolerate any form of discrimination and we are grateful to members of the public reporting this matter to us," they added.
"We are conducting a thorough investigation into the post that was published on X."