Davyd Florian Lincan, aged 23, from Chartist Road, Birmingham, pleaded guilty at Stafford Crown Court to the manslaughter of Stan Bacioiu.
Mr Bacioiu, 44, originally from Romania, died on December 1, 2019, following an assault on Uxbridge Street, Burton, on November 22.
Police were called to reports of men fighting outside an address at around 9.30pm.
A fight involving around 14 people started inside, before spilling out onto the street, where Mr Bacioiu was injured.
Crews from West Midlands Ambulance Service attended the scene before Mr Bacioiu was taken to Nottingham Queen's Hospital - where he eventually died - in critical condition.
The senior investigating officer, detective inspector Zoe Kelsall, from Staffordshire Police's major investigations department, said: "This was a tragic case. Stan was a completely innocent bystander and not involved in the fight.
"Lincan fled the country after the incident and it took some time to locate and extradite him.
"I’d like to thank Stan’s family for their support during this investigation. His window remains in the country alone. Stan was her only family in the UK. Her life has been changed forever."
Lincan will be sentenced at Stafford Crown Court on July 30.