Connor Brown, 18, was allegedly set upon after he left a bar in Sunderland.
The promising boxer died in hospital following a deadly assault in the city centre on Saturday night.
Devastated friends described the “talented young boxer”, from Farringdon, as “one of the nicest lads you could meet”.
Northumbria Police said Connor was assaulted at around 1.30am Sunday morning behind The Borough pub on Vine Place.
Witnesses told how door staff from the nearby Gatsby bar chased a man up an alley before detaining him outside Chillino’s takeaway.
“ Connor Brown was one of the nicest lads I’ve ever known”
Elliot Stephenson, friend
The owner of Gatsby, who asked not to be named, told Newcastle Chronicle: “I’m just incredibly proud of the doormen and all my staff.
“This was an incredibly traumatic thing for them to experience and they were true heroes.”
Connor was taken to hospital with life-threatening injuries but later died.
Flowers and tributes have been left at the scene since Sunday.
A balloon release was also held outside The Dolphin pub in Farringdon.
Friends and family paid emotional tributes to Connor.
Adam Frame shared a video of the balloon release on Facebook, writing: “What a lovely touch, deserves a class sendoff, what a lovely lad he is. RIP Connor Brown.”
Jessika Barrett wrote: “Connor Brown we were blessed to have known you.”
And pal Elliot Stephenson wrote: “Lost for words, Connor Brown was one of the nicest lads I’ve ever known without a doubt.”
He went on: “Always happy and smiling, been taken far too soon, thoughts go out to his family, rest easy brother.”
Friends claim he had shared pictures of himself on Snapchat earlier that night enjoying himself with friends.
Forensics teams are focusing on an alleyway between the Gatsby bar and The Borough, but it isn’t known yet if Connor had been in either before he was attacked.