Two key words: 蹴鞠, the ancient Chinese kick-ball game often called the ancestor of football, and the idiom 一蹴而就 — 'done in a single kick', i.e. accomplished at one stroke.
Left-side foot radical, the compressed side form of 足. Kicking and treading are done with the foot, so this radical anchors the meaning, as in 踢 and 踏.
