Her training has been attributed to a man named Cox or J. Frost. The death of Cox (or alternatively Frost) is associated with a death-bed anecdote about Eleanor's racing prowess where the dying man exclaims to a clergyman, "Depend upon it, that Eleanor is a h—l of a mare!" As a three-year-old in 1801, she became the first filly to win The Derby and also secured The Oaks that year, a feat that would not be repeated until 56 years later when Blink Bonny won both races in 1857. She is the first of only six fillies to win the Epsom Derby, and only four fillies have won the Epsom Oaks and the Derby. Her principal jockey for most of her career was John Saunders. Eleanor retired from racing at age seven and returned to Barton Hall as a broodmare for Bunbury. Eleanor's first race occurred on 20 April in Newmarket at the First Spring meeting where she beat the filly Miss Fuery and won 250 guineas. The Epsom Derby, held on 21 May, was her second career start, which she won against 9 colts and one other filly while carrying 110 pounds. A colt by Fidget (owned by Lord Egremont) was second and the Duke of Grafton's filly Remnant sired by Trumpetor was third. On the day after the Derby, Eleanor won the 550-guinea Epsom Oaks from Lord Grosvenor's filly Rosamond and four other horses. At Ascot, she finished second in a 215-guinea sweepstakes to a colt sired by Asparagus (later named Teddy the Grinder) while carrying 7 pounds more weight than the other racers as a handicap for her wins in the Derby and the Oaks. At the First October meeting in Newmarket, Eleanor won 700 guineas in a match race with Miss Fuery. In her last engagement of the season, Eleanor beat the Duke of Grafton's colt Flambeau in a 200-guinea match race. In her first start as a four-year-old in spring 1802 at Newmarket, Eleanor finished last in a field of four horses to Lord Darlington's horse Muly-Moloch. At the First October meeting in Newmarket, Eleanor regained her three-year-old form and defeated the mare Penelope, winning 350 guineas. She also won the King's Plate from Sister to Gouty a few days later.