This doesnt surprise me, even though Im sure you thought you had him. You went with damage to finish him quick, which would *normally* work. Except hes a long-lived leader whos already playing a strong build.

I suggest treating him and anyone that you suspect has extra stuff (legacies, specs, weapons) like they are winning until theyre literally dead.

A kotegeshi and kanset would have likely won you this fight, instead of going pure damage.

Just a few thoughts. CF is always a surprising place.