Prove Out to the eventual 1973 Horse of the Year. Prove Out also defeated Secretariat's stablemate, the 1972 Kentucky Derby winner and 1973 U.S. Champion Older Horse Riva Ridge, in the 1973 Jockey Club Gold Cup. In addition to his two memorable victories in 1973, Prove Out also ran track record times at Saratoga for 7 furlongs (1:21), and at Belmont Park for 1 miles (1:40). His Woodward Stakes time of 2:25 for 1 miles on an off track is the second fastest performance ever recorded for that distance at Belmont Park, behind only Secretariat's 2:24 record Belmont Stakes win. Prove Out's
Kentucky Derby Challenge Stakes offered a purse of US$150,000 of which $90,000 comes from Churchill Downs and $60,000 from Kempton. In addition, if the race winner exercised their right to run in the Kentucky Derby, they would receive a further $100,000 bonus payment plus would be given an automatic spot in the ensuing two legs of the U.S. Triple Crown series, the Preakness and Belmont Stakes. No European-based horse has ever won the Kentucky Derby. The 2010 race was suspended and the 2009 winner, Mafaaz did not run in the Kentucky Derby, although he did run in the Blue Grass Stakes. Kentucky Derby Challenge