Dude, if you saw that as "Zoro's Humiliation" you're really dumb, that's literally one of the best character developments of Zoro.
He accepts he isn't strong enough yet, he's goal is to become the worlds strongest swordsman, not already be one. He accepted his weakness and he also started respecting Luffy's dream above his own, he showed that back in Thriller Bark, so he doesn't care if its "shameful" to ask for Mihawk for training, because he knows that's how he will get stronger so he can not only achieve his dream, but most importantly he will help Luffy achieve his.