Chax & Karst: discussed your situation with other ES yesterday, we decided that the best way to solve it would be for you to finish the duel from 3-2 score.
If what Karstnator claims is true it definitely has to be 4-2 as mid-game reset would normally be counted as a loss, but it's tough to judge what actually happened as there's no way to proof what that half-finished game was (or how many turns you managed to play before it was reset).
Talked to Karstnator today and he was fine with continuing from 3-2, so it's mainly up to Chax whether to continue playing I suppose. The alternative would be to go with 4-2 score in Karstnator's favor.
I'll also let you extend the deadline by a few days if you can't play until tomorrow due to holidays.