He just wants to beat Clarice? Wow, competitive much?
Well, yes, it is much easier to consider yourself in competition with one other student than thousands!
When I run a 5k or 10k (only lately getting back into that) it is much easier for me to stay ahead of the few behind me than the massive numbers ahead of me.
DS and Clarice, in grammar school, annoyed each other a lot, but now they have mutual respect and encourage each other academically. They even do an on-line game together to de-stress. They still annoy each other with TV shows and politics.

But, for DS, it took off pressure and made it more fun instead of stressing over, "I MUST get a phenomenal score to get scholarships," instead of, "hey, if I beat Clarice, I can choose a day for her to agree with me for one hour. that would be fun, and confusing for other classmates!"
She beat his score freshman year, he beat her score last year, so why not?

(She is better with words, he with math)