Naifu Ejji Desu Matchi Yu yu hakusho : Season 1 Episode 32

With their spirit energies depleted, Yusuke and Chu agree to settle things in a knife-edge death match, an in-your-face, bare-knuckled slugfest where a naked back heel is kept poised before a knife planted in the ground. The first one to lose ground and step back - gets cut.