dethrone
To remove a ruler or champion from the top position.
To dethrone means to remove a king, queen, or other ruler from power. When a monarch is dethroned, they lose their throne and all the authority that comes with it. Throughout history, rulers have been dethroned through revolutions, military defeats, or political upheaval. In 1688, England dethroned King James II and replaced him with new rulers who agreed to limit royal power.
The word works literally when talking about actual royalty, but it's often used figuratively in sports and competition. When a new chess champion defeats the reigning champion, they dethrone them. If your school's debate team loses to another school after winning for three years straight, you could say it has been dethroned. A company that dominates an industry might be dethroned by a competitor with a better product.
The word suggests more than just losing: it implies falling from a position of dominance or supremacy. You wouldn't say someone was dethroned from second place. Being dethroned means you were on top, and now you're not.