According to reports, Ali Issa Ahmad, a 26-year-old resident of Wolverhampton, travelled to the UAE for a holiday in January. The BBC cited the nation's embassy in London as saying Ahmed was "categorically not arrested for wearing a Qatar football shirt", and was charged for wasting police time and making false statements. Medical test, however, showed that the British citizen had caused the injuries by himself.
The UAE's prohibition on "showing sympathy to Qatar" was established in 2017, after the country cut off diplomatic relations with Doha in conjunction with Saudi Arabia, Egypt and Bahrain.
Qatar has vociferously denied the accusations, describing the Saudi-led embargo as a violation of worldwide law and its national sovereignty.
"This is instead an instance of a person seeking media attention and wasting police time", the official said.
The UK's Foreign and Commonwealth Office said it was "providing assistance to a British man arrested in the UAE and are touch with the local authorities".
He was arrested at the match and claimed he was abused by UAE security officials. I am in shock that he was arrested and assaulted because of the football T-shirt he was wearing.
Ahmad was granted one phone call on January 31 following his arrest and that he used to contact his friend Amer Lokie.
Ahmad's reported detention comes more than two months after British academic Matthew Hedges was released by the UAE by a presidential pardon after spending more than six months in prison in an espionage case.
"We are advised he has since admitted those offences and will now be processed through the UAE courts", said a statement posted online.
Lokie said Ahmad was released but it seemed he had then been assaulted by security forces, "went to the police station to report the assault and was accused of. making false allegations against UAE security officials".
On its website, the Foreign Office warns travellers to the UAE of a June 2017 announcement "that showing sympathy for Qatar on social media or by any other means of communication is an offence".
"Offenders could be imprisoned and subject to a substantial fine", it adds.
Radha Stirling, CEO of advocacy group Detained in Dubai, said this was "not the first time an official government version of events drastically differed from that provided by an expatriate in UAE custody".
Qatar won its maiden title after defeating four-time victor Japan 3-1 in the final on Friday.
Qatar fans stayed away because they are not allowed to travel directly to the UAE and feared harassment when they got there.