Russian boxer Maxim Dadashev has died following injuries suffered in his IBF light-welterweight fight against Subriel Matias in Washington on Friday.
The bout was stopped by Dadashev's trainer Buddy McGirt at the end of the 11th round and the 28-year-old was taken to hospital with bleeding on the brain but failed to recover following emergency surgery.
A statement from the Russian Boxing Federation said: "Russian boxer Maxim Dadashev died in the United States as a result of injuries suffered in a fight with Subriel Matias. The Russian Boxing Federation expresses deep condolences to Maxim's family and friends."
Dadashev had won all 13 of his previous fights before the match with Puerto Rican Matias and after receiving heavy punishment in the latter rounds, McGirt called a halt to proceedings at the MGM National Harbor but he failed to wake up from a medically-induced coma.
Former featherweight Carl Frampton led the tributes to Dadashev.
He posted on Twitter:
Promoter Eddie Hearn added: