Akiko has had a few CMOA, but her most recent was putting the audience in their place during Mamiya's fight against Yuuto in Chapter 189 as they practically chanted for the boy to give up. Her anger was so surprising that it caught a raging Nana off guard, who was just seconds from beating the crap out of the Jerkass in front of them.
Akiko: What's wrong with being stubborn? Even if it's lame, even if it's uncool, you don't give up until the very end. What's wrong with that!!? Shut up and watch, morons!!
In chapter 369, we finally learn the full depth of Minami Hiroki's efforts in teaching Minoru. None of the younger members of the karate club knew how strong Minami was, because he always held back or imitated other people's fighting styles to help train them. Despite probably knowing that this cost him some respect from his juniors, Minami continued to do so for their own sake. Then, in Chapter 370, we learn that while Minami isn't holding himself back, he's also not targeting Minoru's weakest point. If he did, it would guarantee victory, but Minami wants more than anyone to see Minoru succeed at his dreams, and he just can't bring himself to be merciless in their fight, so he's leaving a single slim chance by letting Minoru keep using his legs. And this is the 'Emperor of Dirty Matches' we're talking about.
The entire tournament is a great CMOA overall for Minami, as he defeats opponents that most people would never expect him to beat, and he did it with minimal injuries.