Now I'm thinking it's more his integrity.
Seriously, when was the last time you saw someone as gracious in defeat as this guy? Gives the challenge his all, gets his ass kicked, but accepts it. Finds his comatose ex-opponent, keeps an eye on him instead of finishing him off. Damn near handed Wakanda on a platter and passes. At every turn this guy is embodying "I'm going to do this right or I'm not doing it."
All that, badass and smartass too.
It's a complete reversal of the mindset of "it's not whether or not I'll win but which method will let me do so" that shows up in so many protagonists (not to mention video game design in general. Not to rag on gamers, but graceful loss is not something the medium is good at accommodating).