You can get sanc without using another PC you know.
Not saying he did, but I am also saying you don't know for sure that he didn't. You don't want to make assumptions and base complaints/comments off of those.

When a rager challenged me to a solo fight, I could put up A/S stoneskin/haste/fly spiderhands enlarge/reduce and yes, even sanc if I wanted to, without getting anything from anyone. Usually I put up less because they would realize they had no chance and flee.

Oddly enough, a warrior can do all those things as well, he may not in every fight, but he has the ability to do so. People are going to stack fights in their favor- that is why the whole approach of "I challenge you to a duel" is sort of moronic. You're giving them a set fight they can then prep for, where they know where you are- so you're probably not keeping up preps all the time, while he puts everything up right before he engages.

The better way is to catch them when they're NOT expecting the fight, not prepped, and just stomp them in three rounds. Or run him around making him think you're terrified and just engaging every other hour or so just to see if any of his preps fell. Overconfidence gets many a person killed.