High Quality Content by WIKIPEDIA articles! Dawn Run (1978–1986) was a Thoroughbred racehorse (Deep Run - Twilight Slave) who was the most successful racemare in the history of National Hunt racing. She won the Champion Hurdle at the Cheltenham racing festival in 1984 and the Cheltenham Gold Cup over fences at the festival in 1986. Dawn Run was the only racehorse to have completed the Champion Hurdle - Gold Cup double. She was one of only two mares who have managed to win the Champion Hurdle, and of only four who have won the Cheltenham Gold Cup. She was also the only horse ever to complete the English, Irish and French Champion Hurdle treble.