British boxer Scott Westgarth has died aged 31 after being hospitalised following his decision win over Dec Spelman at the Doncaster Dome on Saturday.
Westgarth conducted a post-fight interview following his 10-round victory in the England light-heavyweight title eliminator, but fell ill backstage and was attended by paramedics.
He was taken to the Royal Hallamshire hospital and died in the early hours on Sunday, the British Boxing Board of Control has confirmed.
The board's general secretary Robert Smith said: "It's a terrible thing that's happened. My condolences to all of his family."
Organisers cancelled the rest of the show, where former professional footballer Curtis Woodhouse had been due to make his boxing comeback against John Wayne Hibbert.
Westgarth was a former ski instructor who worked as a chef at Sheffield's Royal Victoria Holiday Inn, having lived in Penistone and originated from the north-east.
The promoter on Saturday night, Stefy Bull, and Westgarth's opponent, Spelman, were joined by many of British boxing's biggest names in expressing their condolences.