Los Angeles - US fighter Patrick Day was hospitalized after a brutal knockout by unbeaten Charles Conwell in a super welterweight bout in Chicago on Saturday.
Fight broadcaster DAZN reported Day, who was taken from the ring on a stretcher, did not regain consciousness before leaving the Wintrust Arena and had a seizure as he was put in an ambulance.
Conwell had dropped 27-year-old Day in the fourth and eighth rounds and knocked him out with a massive left hook in the 10th round.
The fight was on the undercard of Russian Dmitry Bivol's World Boxing Association light-heavyweight world title defense against Lenin Castillo.
The co-feature on the card is former undisputed cruiserweight champion Oleksandr Usyk's heavyweight debut against Chazz Witherspoon.