Boxer Scott Westgarth became ill after fighting in the UK's Doncaster Ring. She was taken to the hospital on an urgent ambulance basis.
The 31-year-old boxer's opponent was Deck Spellman in the fight last Saturday.
Talking to journalists at the end of the victory, she suddenly became sore with pain. He was taken to a hospital where he became seriously ill. Later he died there.
His last rival Spellman has expressed his heartfelt condolences on Scott's death. On Twitter, he wrote, "I'm shocked! I do not have the language to speak. My condolences to the family of Scott. '
Canada's boxer Tim Hughes died the same way in June last year after winning the bat. Scotland's Mike Towell died of brain injury in 2016, in September.