American boxer Patrick Day died Wednesday after suffering a serious brain injury during his knockout defeat to Charles Conwell last weekend, promoter Lou DiBella said in a statement.

The 27-year-old super welterweight had undergone emergency surgery after being knocked out by Conwell on Saturday at Chicago’s Wintrust Arena.

“On behalf of Patrick’s family, team, and those closest to him, we are grateful for the prayers, expressions of support and outpouring of love for Pat that have been so obvious since his injury,” DiBella said.

Day, who had been in a coma following surgery at Northwestern Memorial hospital, died surrounded by family and friends.

The American fighter had been carried unconscious from the ring on a stretcher on Saturday following his 10th round knockout.