If you mean the very first time I fought the Werewolf, yes I did survive… Because I was with friends, and we were all playing Pokemon when pets were still super strong 
Now if you mean the first time I fought it solo, I still survived quite easily, because back then stamina cost was quite low and all you had to do was take a Katana, dash through the boss, spam light attacks until it died, fully staggered, unable to attack you.
→ There also used to be a perk that boosted light attack damage, which helped.
Now I have to admit that if you’re playing with high latency, things can get rough, even against a crocodile XD
But if I’m not having a huge lag spike, I will never die to the Arena Champion… Just pick the right perks 
→ The Arena Champion hits so hard that your armor and health do not matter, so max out grit and pick Steel Thewed; this way even if you mess it up, you simply do not get one shot, you just roll, heal, and go back in.
→ That being said, the Arena Champion is much easier than the Werewolf, she is just a human NPC, so pick a weapon that can knock her down (1H Sword or Axe both work really well).
Before the Age of War, you could use the same Katana tactic because you dashed through her and staggered her to death with light attacks, but not anymore due to stamina costs.
↳ Now to the question of whether I died to the Arena Champion solo, the answer is yes.
Back when I dropped playing with followers, pets and thralls, I started soloing everything with daggers.
Then I found out some bosses should be fought with a shield.
But neither of those were reliable against the Arena Champion (she eats your stamina with shield, and NPCs could break out of stunlock which was enough to die with daggers)
I quickly found that you should fight the Arena Champion alone and just watch her attack before you engage. She becomes extremely predictable, and thus, not a threat anymore since she will never hit you… Except if you’re lagging hard, but that’s not exactly part of the game design, it is artificial difficulty.
So the real question is, if you’re playing in Single-Player, thus with no latency, is there really anything that can kill you?