In a 2006 interview director Walter Hill mentioned that he had been critical of the performance of Jill Ireland, who was Charles Bronson's wife at the time. When Hill went to Bronson's home to discuss this, Bronson wouldn't shake his hand--he just showed Hill in and poured him a drink. Hill said that he would have liked to have worked with Bronson on other films, but that Bronson refused to work with Hill again.
The most grueling filming was the climactic match between Charles Bronson's character and the fighter promoted by Michael McGuire's character. Shooting took more than a week because of the fight's complicated movements. It was filmed in a riverfront warehouse on Tchoupitoulas Street, a very rough area. Bronson and Nick Dimitri spent days squaring off under the hot lights, watched intently by McGuire and his hoods, James Coburn, Strother Martin, and a few dozen cameramen, technicians and crew members. To create the illusion of being a seafood warehouse, several Styrofoam oyster bins were stocked with real, very smelly oyster shells. An attempt to cloak the fumes with a commercial disinfectant made the smell worse.
According to Walter Hill, Charles Bronson "was in remarkable physical condition for a guy his age; I think he was about 52 at the time. He had excellent coordination, and a splendid build. His one problem was that he was a smoker, so he didn't have a lot of stamina. I mean, he probably could have kicked anybody's ass on that movie, but he couldn't fight much longer than 30 or 40 seconds."