Brazilian midfielder Taison was sent off after he reacted to alleged racist abuse during Shakhtar Donetsk’s 1-0 home win against Dynamo Kyiv.
Taison, 31, made a gesture towards the Dynamo fans and kicked the ball at them before the referee took the players off the pitch in the 77th minute.
When they returned five minutes later, Taison was shown a red card.
Shakhtar said both Taison and fellow Brazilian Dentinho were targeted and the Dynamo fans were warned twice.
Video on social media shows both Brazilians in tears.
Speaking after the Ukrainian Premier League match, Shakhtar manager Luis Castro said: “I want to support absolutely everyone suffering from racism and the guys who have suffered today.
“Any manifestations of racism are absolutely unacceptable. It was, is, and will be a disgrace to everyone. Together, we must fight it – every day, every minute and every second.”
In a club statement, Shakhtar said they “categorically oppose any manifestations and forms of racism, racial discrimination, xenophobia, and any related intolerance”.
Shakhtar added: “There can be no justification of those who insult other people because of their skin colour, religious, or political beliefs. This kind of behaviour is unacceptable in any civilized countries and football leagues.
“Such humiliating accidents cause pain and disappointment to the large football family of FC Shakhtar. We condemn this kind of behaviour of the audience, we will always voice the support and protect our players. We are calling on football authorities and clubs to stop racism in the stadiums.”
In a tweet after the game, Dynamo wrote “#NoToRacism”. BBC Sport has approached the club for a comment.
Last week in Italy’s Serie A, Brescia’s Mario Balotelli kicked the ball into the crowd and threatened to walk off the pitch after being abused in a 2-1 defeat at Verona.