One in a Million was a small, lightly-built[2] bay filly with a faint white star bred in Ireland by the County Limerick-based Mount Coote Stud.
[3] As a yearling, the filly was sent to the Newmarket Houghton sales in October 1977 and was bought for 18,500 guineas[4] by the bloodstock agent Richard Galpin,[5] on behalf of Egon Weinfeld, who raced her in the black and white colours of his company Helena Springfield Ltd.
She was made favourite for the race after reports that she had performed impressively in a training gallop against her stable companions Formulate and Odeon who had finished first and second in the Hoover Fillies' Mile.
After tracking the leaders until the final furlong, One in a Million produced what Timeform described as an "electrifying burst"[4] of acceleration to take the lead and win easily by one and a half lengths from Lyric Dance.
Her main rivals appeared to be Pitasia (Prix Robert Papin, Critérium des Pouliches), Topsy (Fred Darling Stakes) and Lyric Dance (Free Handicap).
She took the lead early in the straight and looked likely to win easily but in the final furlong she was overtaken by the outsider Buz Kashi and was beaten one and a half lengths into second place.
She was awarded the race after an inquiry by the racecourse stewards, who disqualified Buz Kashi for causing interference to Lightning Record two furlongs from the finish.