How I Lose Bets With My Sadistic Gifted Childhood Friend and She Steals All of My Firsts

Wakaba Yoshizawa has a childhood friend named Komaki Umezono.

This girl wore the mask of an honor student with good morals who's blessed with both beauty and brains, but in reality she's an evil genius who looked down on people. For the sake of regaining the dignity she lost to Komaki, Wakaba challenges her to a match, but Komaki tells her "Each time I win, I will take one precious thing from you." as a condition!? Every time she loses to the girl she "hates", her true feelings get exposed.

(Source: Young Ace Up)