Newcastle United winger Rolando Aarons and members of his family clashed with at least five men in trendy Quayside bar Lively.
The England under-20 player, his mum Joan Jacob, 46, and four others were originally charged with violent disorder but the prosecution accepted their guilty pleas to the lesser charge of affray.
Judge Edward Bindloss, sitting at Newcastle Crown Court, warned jail was a possibility and said the 90-second brawl at 2am in October 2016 was “a serious incident with personal violence being used and items being thrown”.
One man in the other group suffered a “nasty” head injury, Judge Bindloss said, though this was caused indirectly after door staff intervened.
The judge said: “Rolando Aarons and family and friends were celebrating a birthday and they were in Livello.
“There was no indication of any trouble
“CCTV shows this incident blew up out of nowhere and suddenly there is a large melee involving numerous people.”
Judge Bindloss said the injured man was hurt when door staff tried to escort him away from trouble – though he stressed there was no criticism of the doormen working that night.
The venue has been compensated for damage caused, the judge said.
Only the injured man from the other group had made a witness statement and his friends had not helped police, the court heard.
The judge added: “Some of them were clearly involved in using violence against Aarons and his family and friends.”
A member of the other group was the first to throw anything, the judge said.
“It can be said he escalated the incident.”
Aarons, who was born in Jamaica and raised in Bristol, made an immediate impact when he broke into the Newcastle United first team.
But the 22-year-old suffered injury set-backs and has now been loaned out to Hellas Verona in Italy.
The defendants were Aarons and his mother, both of Montagu Avenue, Gosforth, Newcastle; his cousin Garfield White, 23, a serving prisoner formerly of Wordsworth Road, Bristol and his friends Kallum Phillips, 23, of Kensington Park, Bristol, and Jamar Collins, 22, of Walker Close, Bristol.
Charges were dropped against White’s sister Sabrina, 24, after it was accepted she acted as a peace-maker on the night.
The judge granted all defendants bail, except for Garfield White, ahead of sentencing on May 22.
The judge said: “All options remain open, including an immediate custodial sentence.”