I'm no expert on Ryfivin; I saw maybe two or three of his fights. However, on one of those occassions I saw him get killed making what I would call a newbie mistake. It's possible you were having an off-day and everything else you ever did was flawless, but I'm guessing not.

I'm not denying you're good at playing a thief, but it might be less like NBA all star team good and more like starter on a high school basketball team good. As long as you're willing to admit you can make mistakes and learn from them, you're going to constantly get better. Once you become so much in love with how good you think you are that you can't admit a mistake you made, rather than some power imbalance, was absolutely responsible for an undesired outcome, you're as skilled as you're ever going to be.