Japan narrowly outpointed his better-fancied stable companion Mount Everest to land the Group Two spoils in the Beresford Stakes at Naas.
Mohawk led home a one-two-three for Aidan O’Brien in the Juddmonte Royal Lodge Stakes at Newmarket.
Ten Sovereigns will bid to cement his position as a leading candidate for Classic honours next year when he takes centre stage in the Juddmonte Middle Park Stakes at Newmarket on Saturday.
U S Navy Flag has pleased connections as he settles into his new surroundings ahead of The Everest next month.
33 trainers have entered 64 horses for Series Final at Naas on Sunday October 21
Champions Series stars Alpha Centurai and Saxon Warrior have both been retired after suffering injuries at Leopardstown on Saturday.