Striker Palmer accused supporters of racist abuse when the teams met in the Championship last Saturday.

A man was later arrested on suspicion of a racially aggravated public order offence and released on bail, South Yorkshire Police said.

On Friday, Palmer was jeered when he missed a first-half chance and then loudly booed after being booked and again when he was substituted after the break during the 1-1 draw.

Robins said: "The reaction was a disgrace. People need to have a look at themselves.

"What are they doing? It's ridiculous. It's a joke - an absolute joke. It shouldn't happen.

"Kasey's a football player with family and wants to play and enjoy his football like everyone else. Then you've got these idiots, absolute clowns."

Sheffield Wednesday boss Danny Rohl said the club had sent out a clear message regarding last weekend's alleged racist incident.

When asked if the cup tie booing undermined the Owls' zero-tolerance stance, he said: "It was more important we showed last week, a clear direction from everybody, my team, from the fans, from the club side and I think the statement showed what we think about such situations.

"We cannot accept this, we will not accept this. If we see something or hear something, I think then we have to take responsibility of course. Everybody is involved and has to do something."

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The same day as the first incident at Hillsborough, AC Milan's players walked off the pitch during their game at Udinese's Bluenergy Stadium after goalkeeper Mike Maignan complained to the referee that he was being racially abused.

Four Udinese fans have been banned for life by the Serie A club.

FIFA president Gianni Infantino called for clubs whose fans committed racial abuse to forfeit games as punishment.

The Professional Football Association (PFA) called for tougher action by authorities in stamping out racism after the first incident.

PFA Chair Omar Beckles said: "Our members want to see real, consistent and significant consequences for racist abuse, both for the individuals who are responsible and for clubs who fail to get a grip of the issue within their stadiums.

"The reality is that players don't believe this is happening. The responsibility for what happens next lies with the authorities."

Coventry and Sheffield Wednesday will meet again for a fourth round replay at The Coventry Building Society Arena.