Prix d'Ispahan
Trillion had an outstanding year in 1978 when she won the Prix Foy, her first of two consecutive editions of the Prix Dollar, and the Group One Prix Ganay. She also had strong second-place performances in the Prix d'Ispahan, Grand Prix de Saint-Cloud and, ( her usual jockey Lester Piggott riding Alleged) she was ridden by American superstar jockey Bill Shoemaker, finished second behind winner Alleged in the Prix de l'Arc de Triomphe.