Khan relied heavily on tanking hits rather than avoiding damage, and while he might have the durability to take a few stabs and keep fighting effectively, I think the combination of the strikes he will be taking from Buckys arm and the stabs he will be receiving via Buckys exceptional h2h skill will win out in the end. If Khan was as skilled as bucky or even widow, id say his durability would be enough to tank the hits to get in close and choke a muther out. He could still go that way, but I don't think it will, Bucky after a hard fought fight.