When Kagura is first introduced in Azumanga Daioh, she sees herself as a friendly rival to Sakaki. Sakaki’s naturally athletic and excels in all sports-related things, but doesn’t really care about sports and just likes thinking about cats and stuff. I think even by the end of the series this dynamic dies down quite a bit, though, with Kagura becoming more just part of the group and filling a role in the Knuckleheads group as touched on in previous Asks. So they’re not being too competitive here, but I hope everyone will be okay with that.