A club-goer was stabbed and police Tasers were used four times during a violent brawl outside a Broad Street nightclub.
A total of 45 police officers were needed to suppress the disorder, thought to be gang related, outside the Rococo Bar.
Police said Tasers were needed to stop fighting among a crowd of up to 150 people in the street at about 12.40am on Wednesday.
At the same time, there was violent brawling inside Rococo which was filled with 400 more clubbers.
One man, who police say was at the bar that evening, was treated for stab injuries at City Hospital and an attempted murder investigation is under way.
Details of the mass brawl emerged as city licensing chiefs decided to close the bar late on Tuesdays and introduce new police controls throughout the week.
But Rococo management insisted that the brawl was not as severe as police claim, that most trouble happened off the premises and that a DJ, who has since been dropped, had contributed to the large crowds present.
Police Licensing officer Abdool Rohoman described Tuesday and Sunday nights at Rococo, where heavy urban music is played, as popular with gang nominals and as such viewed as 'high risk' by police.
He said: "It is the most lucrative night for the business.
"There are people drinking the most expensive Champagne - the gang nominals spend a lot of money on these premises.
"There is direct link between the violence on Tuesday and the people who go to the club." He explained that police, who sent every available officer to the brawl, concentrated their manpower on breaking up the fighting in the street rather than make arrests or deal with the fighting they could see going on inside the bar.
But he added: "People, including known gang members, were seen leaving the premises with head injuries, hand injuries, there was lots of blood."
He stressed that officers are only permitted to use a Taser with a warning, if there is a serious threat of violence to an officer or member of the public.
Solicitor Heath Thomas, representing Rococo, said that there had been a larger than usual Tuesday night crowd because the host, DJ Silk, had been heavily promoting it without the company's permission.
He said that on other nights of the week there were no problems and added that the disorder inside involved a small group of men.
He accused police of not sharing intelligence over gang activity on the night with the management.
"Most of the problems occurred outside of the premises. I think we have been set up to fail," he said.
The licensing committee decided to close the bar from 10pm Tuesdays until 10am Wednesdays and that any other changes to staffing, hours and entertainment must be approved in advance by police.
A full licensing review will be held within four weeks.