Best Match 2017 (ベストマッチ2017 Besuto Matchi Nisen-jūnana) is the second episode of Kamen Rider Zi-O. It is the second part of the Kamen Rider Build tribute arc. It features the full debut of Geiz's GhostArmor after its brief appearance at the end of episode 1 and the series debut of Zi-O's BuildArmor after its appearance in Kamen Rider Build: Be The One. Emu Hojo makes a brief return at the end of this episode.
This episode is accompanied by the second episode of Kamen Rider Zi-O: Supplementary Plan web series, Rules of the World.
Sougo is attacked by a Kamen Rider from the future, Geiz Myokoin, but is saved by a girl from the same future Tsukuyomi, who wishes to help him out. With no clear idea of what is going on, his confusions are further pushed with frequent visits from the mysterious prophet named Woz. Meanwhile Another Build is wreaking havoc, and Sougo discovers that the key to defeating this "Kamen Rider Build" is to meet Sento Kiryu.