Celtic manager Ronny Deila has hit out at Scottish Football Association disciplinary rules after Aleksandar Tonev's seven-match ban for racist language was upheld.
Tonev was described as neither a credible nor a reliable witness by an SFA-appointed judicial panel in a report that was published following the failure of his appeal.
The report revealed Aberdeen defender Shay Logan had accused Tonev of calling him a "black c***" during a Scottish Premiership match on September 13 and the panel found the on-loan Aston Villa winger guilty after describing the Dons player as an "impressive witness".
The SFA's disciplinary rules, like civil court cases, do not require that guilt be established beyond reasonable doubt, unlike criminal cases.
The criteria for finding Tonev guilty was summed up in the report as ''it is more likely than not that the subject of the complaint committed the act of misconduct alleged''.
But Deila feels more proof was needed - no one else heard the offending words, although Logan quickly told others.
The Norwegian said: "You can't judge a person on word against word, in my opinion. You will never do that in any real court. There is no proof and we still believe him. We will continue to do that when we don't have any other proof.
"You call another person a racist just on a word? I can't understand this happening.
"For me, if you are going to judge someone you have to do it with real proof and not word against word. Because a Bulgarian guy, with not very good English, is going to defend himself? Not so easy."
Celtic vowed to address issues raised in the proceedings with the SFA but there appears to be no recourse for challenging the decision again.
"I don't think there is any possibility to go further," Deila said. "We have to take the penalty but we still feel it is not right and we believe Aleksandar in full."
Celtic have consistently stood by Tonev and there appears little chance of him being returned to Aston Villa midway through his season-long loan.
"He still has a future here," Deila said. "Of course it is going to be difficult being seven games out but that's football. The most important thing is we stay behind him and support him.
"We are going to give him some days off to go to Bulgaria for Christmas and when he comes back he will be fighting to get back in the team.
"He is very disappointed of course but he moves on. He knows his innocence and he will just keep on going."
The damning nature of the report might make it difficult for Tonev when going to opposition grounds but Deila does not feel the player will be universally condemned. "I think football fans are clever people as well," he said.
"They can see behind the case and behind the results as well. I say we have to have proof."
And he feels the 24-year-old will still want to play in Scotland.
"I think so but I haven't talked a lot about this," Deila said.
"But he is training well for the two days and he seems good."