Simiso Buthelezi, a South African boxer, died in hospital after suffering a head injury during a loss in Durban on Sunday.

Buthelezi had to be stopped by the referee for throwing punches at thin air and seemingly fighting an unseen opponent in the lightweight battle. Buthelezi was in command of the battle in the tenth round, forcing his opponent through the ropes after a seemingly benign exchange.

Buthelezi took a strong jab to the chin from his opponent before collapsing and briefly slumping onto the ropes, according to replays. Buthelezi appeared to lose his bearings when the action resumed.

Instead of heading toward his opponent, he focused on the referee and didn’t seem to notice when the office moved out of the way. He was left staring at an empty corner of the ring, punching an unidentified opponent.

As a result, the bout was promptly stopped by the referee, and Buthelezi was rushed to the hospital. He was put into an induced coma at first, but it was revealed on Wednesday that he had died.

“It is with great grief that Boxing South Africa and the Buthelezi family announce the demise of Mr. Simiso Buthelezi, who passed away last night at hospital in Durban,” said a joint statement.

“Boxing South Africa will perform an independent medical examination of the injury and make the results of that examination public. The Buthelezi family and Boxing South Africa acknowledge the Minister’s heartfelt condolences.”