Tupai said he had planned on getting away from the gang members but can't remember what took place next.
His boss - who was also at the bar - later told Tupai's family that he had found Tupai outside the bar badly injured and talking with a security guard.
Tupai had stumbled "crooked and smashed" up to the guard seeking help, his boss said.
"Apparently I was walking to him with bruised face, horrible looking, asking him for help," Tupai said.
• Police are appealing for any witnesses or anyone who knows the identity of the offenders to call Police on 09 261 1321 or Crimestoppers anonymously on 0800 555 111.