Tony Liberatore admits to punching Matthew Knights during the Bulldogs' clash with Richmond in 2001.
"I took things into my own hands, I probably shouldn't have done what I'd done," Liberatore told Fox Footy's Open Mike.
"He was niggling one of our wingmen, Matthew Robbins, and I thought he's pretty fired up.
"From the corner of my eye I thought he was going to come through and collect me. I just felt that something was going to happen, so unfortunately I did what Charlie Sutton told me. I got in first."