Willian demanded "proper sanctions" be imposed on Dynamo Kiev after fellow Brazil international and former Shakhtar Donetsk team-mate Taison was racially abused by supporters in Sunday's Klasychne derby.
Taison led a Shakhtar counter-attack deep into the second half in Kharkiv before fouling Dynamo defender Artem Shabanov, to which the visiting fans in that corner of the stadium reacted with racist chants.
The forward reacted by showing his middle finger to those responsible and then booting the ball towards them, before referee Mykola Balakin ushered the teams off the pitch as per UEFA protocol, with Taison and fellow Brazilian Dentinho in tears.
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Upon the teams' re-emergence a few minutes later, Balakin showed Taison a straight red card much to the former Metalist star's bemusement.
Shakhtar and its coach Luis Castro released strongly worded statements after the match and Willian – a former team-mate of Taison's at Shakhtar and with Brazil – urged the authorities to take "proper" action after the Ukrainian Premier League pledged to prosecute those identified as responsible.
Speaking ahead of Brazil's upcoming clash with Argentina, Willian said: "It's another sad episode for football. We players must do whatever we can to make sure this stops, but the institutions, federations have a greater responsibility on this.
"They must address these situations when they happen and apply the proper sanctions to make sure this kind of thing stops once and for all. These situations make me sad."
Taison also addressed the incident on his official Instagram account, vowing to never allow such intolerance to silence him.
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He wrote: "I love my race, I fight for colour, whatever I do is for us, for love. I will never shut up in the face of such an inhuman and despicable act! My tears were of indignation, repudiation and helplessness, helplessness that I could do nothing at that moment!
"But we are taught early on to be strong and to fight! Fight for our rights and for equality! My role is to fight, to beat my chest, to lift my head and keep fighting always!
"In a racist society, it is not enough not to be racist, we must be anti-racist! Football needs more respect; the world needs more respect! Thank you all for the support messages! We continue the fight."