After recovering from illness to win the 1000 Guineas in April 1965 her form deteriorated, with a second place at Royal Ascot being her only notable performance in five subsequent races.
Night Off was a bay mare with no white markings[1] bred by her owner, Major Lionel Brook Holliday at his Cleaboy stud in County Westmeath.
[2] Night Off was the most notable racehorse sired by Holliday's stallion Narrator, who won the Champion Stakes and the Coronation Cup for his owner in the mid-1950s.
[3] At the same course in late September she was moved up in class to contest the Cheveley Park Stakes, Britain's most prestigious race for two-year-old fillies.
[4] In the Free Handicap, a rating of the best two-year-olds to have raced in Britain that year, she was the top-rated filly, nine pounds behind the leading colt Double Jump.
[5] In their book A Century of Champions, based on a modified version of the Timeform system John Randall and Tony Morris rated Night Off a "poor" winner of the 1000 Guineas.