Yuki wasn't the smartest student in the school. In fact, even among his friends, he was still the second best behind Kato, a fact he had no shame in admitting. While it was clear that he was smart enough to be among the top three in the class, he never put much effort into his studies, and he was fine with that; after all, it wasn't his passion.
Nevertheless, Yuki was still proud of his intellect. Although he had never applied himself too much to studying, everything came easily to him. He excelled in mathematics, was slightly above average in physics, and thanks to his participation in the chemistry club, that subject felt like a walk in the park for him.
So, yes, he was proud of his achievements as a student.
However, he started to doubt his intelligence, and it was all because of the blonde boy in front of him.