People are misunderstanding the fight. It wasn't just a fight to remind us of how big Kaname's dick is, but how Inukai got shafted into the background as the plot progressed. Inukai had this pretty big rival bro vibe early on, but as the series has escalated he hasn't done much except watch shit go on. This fight was a chance for him to do something for himself and learn not only what Kaname HAD, but what he Inukai was MISSING.
By the end of the fight, it was basically a clash of ideas and perspectives which boils down what Kaname said at the end, "What you were competing in was a D-Game. Not a martial arts match."
Hope the author goes further with this because a lot of the characters in Kaname's squad don't really have much personality aside from when they were first introduced. Some more glimpses into their pasts or chapters focused on them would be nice. Like I feel like the author's forgotten that Sui is supposed to be "harboring" her twins brother's soul inside her body. We also haven't really gotten much info about Shuka's family situation since she's pretty fucking rich and that wasn't even a result of converting D-Points.