The row between Chelsea manager Jose Mourinho and Uefa seems set to escalate with Mourinho threatening to take legal action unless the Uefa official who branded him an “enemy of football” apologises.

Uefa referees’ committee chairman Volker Roth accused Mourinho in the aftermath of Anders Frisk’s retirement.

Mourinho had criticised the referee’s display against Barcelona in the Champions League and the Swede had subsequently received death threats from irate Chelsea supporters.

“Mr Roth has two ways out, apologise or it goes to court,” Mourinho said.

Mourinho criticised Frisk’s performance in Chelsea’s Champions League visit to Barcelona, and accused the referee of talking with home boss Frank Rijkaard during the half-time break.

Frisk, meanwhile, is adamant that his decision to quit was the right one.

“I spoke to Volker Roth, who tried to make me go back on my decision but I’m finished. I’m relieved and my gut feeling tells me it’s right,” he said.

“I feel like a hunted animal and I don’t want a life like that. You never know what these people might do.

“Coaches and managers should pause to think what they might start by saying something off the cuff.

“When a referee’s decision starts this type of reaction, it’s no use any more.”

Mourinho added: “It’s a shame that Frisk has decided to leave football.

“If, as some people have suggested, this decision is linked to the criticism of his performance in the Barcelona game, it seems strange to me.

“There’s similar criticism every day, all around the world, for managers, directors and players. It’s a normal situation.

“A referee with the experience of Mr Frisk would not take such a drastic decision because of criticism of his performance at Barcelona.

“If there are other motives I do not know them and would like them to be known.

“If it has something to do with the threats – which should obviously be condemned – then it is a police case.”

Chelsea have said they will act if it can be proven that their own supporters made the threats that convinced Frisk to retire.

A club statement said: “The club and our manager condemn any threats made to Mr Frisk, his family or friends.

“If there is any evidence of such behaviour by Chelsea fans then we would totally disassociate ourselves from them.

“We would welcome any such evidence to be passed to us so we can investigate and take the appropriate action.”