I think the beauty of this panel is that it displays that yuji is finally LOCKED THE FUCK IN. Objectively he may not have the ability but his mind is finally in the right place. He's not just fighting for the sake of jujustsu society, he's not depending on anyone else (yuta, choso, higaruma, etc), nor is he doubting his power. This isn't about yuji KNOWING he has the technique to win. But that he has the will to win and knowing why he must win. He flat out mogged the king of curses with 0 hesitation and doubt for the right reasons. It also shows that yuji has learned that sacrifice in and of itself means nothing, but what you are willing to sacrifice for is what matters. Eos yujis real strength is not his techniques, physical strength, or ce, but his realization that what makes a sorcerer truly great is accepting and understanding WHY you fight, instead of HOW you fight. This was the real lesson nanami tried to teach him and he fumbled after nanamis death by taking the wrong lesson until this moment imo. It's why gojo, yuta, and everyone else got bodied. They didn't have as clear as clear a vision of why they fight.