He used his speed, attacking with aggressive intensity and twisting to keep Samehada from getting a good hit on him as he did. He was going to stay in close and he was going to hold the attack as long as possible. He had the strong sense that the spar was coming to a close, after all, and he didn't want to waste such a prime opportunity.

The only upside here was that he was particularly resistant to heat, and it would take longer for him to get burns. However, he wasn't impermeable, and it would still happen if he lingered too long.