Prove Out was an American

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 thoroughbred

Thoroughbred

The Thoroughbred is a horse breed best known for its use in horse racing. Although the word thoroughbred is sometimes used to refer to any breed of purebred horse, it technically refers only to the Thoroughbred breed...

 racehorse who, under the training of H. Allen Jerkens

H. Allen Jerkens

Harry Allen Jerkens is an American Thoroughbred race horse Hall of Fame trainer.Jerkens' father owned a riding academy on Long Island that led to his interest in horse racing and in 1950 he trained his first winner. Sometimes called the "Giant Killer", he is best known for his upsets...

, scored a 16:1 upset victory over Secretariat

Secretariat (horse)

Secretariat was an American Thoroughbred racehorse, that in 1973 became the first U.S. Triple Crown champion in 25 years, setting new race records in two of the three events in the Series—the Kentucky Derby , and the Belmont Stakes —records that still stand today.Secretariat was sired by Bold...

 in the 1973 Woodward Stakes

Woodward Stakes

The Woodward Stakes is an American Grade I stakes race and is one of the premier races for older thoroughbred horses in the United States. Named for prominent racehorse owner, George Nicholas Woodward, it is run at 1⅛ miles on the dirt for a purse of $750,000.The Woodward was run as a handicap in...

, while conceding 7 pounds to the Triple Crown

Triple Crown of Thoroughbred Racing

The Triple Crown of Thoroughbred Racing consists of three races for three-year-old Thoroughbred horses. Winning all three of these Thoroughbred horse races is considered the greatest accomplishment of a Thoroughbred racehorse...

 winner. Prove Out also defeated Secretariat's stablemate, the 1972 Kentucky Derby

Kentucky Derby

The Kentucky Derby is a Grade I stakes race for three-year-old Thoroughbred horses, held annually in Louisville, Kentucky, United States on the first Saturday in May, capping the two-week-long Kentucky Derby Festival. The race is one and a quarter mile at Churchill Downs. Colts and geldings carry...

 winner Riva Ridge

Riva Ridge

Riva Ridge was a thoroughbred racehorse, the winner of the 1972 Kentucky Derby and Belmont Stakes. A son of First Landing out of Iberia , he was owned and bred by the Meadow Stable of Christopher Chenery. The horse's name came from Chenery's son-in-law, John Tweedy, who was a soldier in World War...

, in the 1973 Jockey Club Gold Cup

Jockey Club Gold Cup

The Jockey Club Gold Cup, established in 1919, is a prestigious thoroughbred flat race open to horses of either gender three-years-old and up. It is typically the main event of the fall meeting at Belmont Park, just as the Belmont Stakes is of the spring meeting and the Travers Stakes is of the...

.

In addition to his two memorable victories in 1973, Prove Out also ran track record times at Saratoga

Saratoga Race Course

Saratoga Race Course is a Thoroughbred horse racing track in Saratoga Springs, New York, United States. It opened on August 3, 1863, and is the oldest organized sporting venue of any kind in the United States. It is typically open for racing from late July through early September.-History:John...

 for 7 furlongs (1:21), and at Belmont Park

Belmont Park

Belmont Park is a major thoroughbred horse-racing facility located in Elmont in the Town of Hempstead in Nassau County, New York, on Long Island adjoining New York City. It first opened on May 4, 1905...

 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

Belmont Stakes

The Belmont Stakes is an American Grade I stakes Thoroughbred horse race held every June at Belmont Park in Elmont, New York. It is a 1.5-mile horse race, open to three year old Thoroughbreds. Colts and geldings carry a weight of 126 pounds ; fillies carry 121 pounds...

 win. Prove Out's winning performance in the 2 mile Jockey Club Gold Cup was timed in 3:20, bettered in American racing only by the great Kelso

Kelso (horse)

Kelso was an American thoroughbred race horse considered among the best racehorses of the 20th century. In the list of the top 100 U.S. thoroughbred champions of the 20th Century by The Blood-Horse magazine Kelso ranks 4th, behind only Man o' War , Secretariat and Citation...

. In a span of 2 months Prove Out decisively defeated 4 Hall of Fame

National Museum of Racing and Hall of Fame

The National Museum of Racing and Hall of Fame was founded in 1950 in Saratoga Springs, New York, to honor the achievements of American thoroughbred race horses, jockeys, and trainers...

 horses: Forego

Forego

Forego was an American Thoroughbred racehorse that won eight Eclipse Awards including Horse of the Year, Champion Handicap Horse and Champion Sprinter....

, Secretariat, Cougar II

Cougar II

Cougar II was a Chilean Thoroughbred racehorse who also competed in theUnited States where he was inducted in the National Museum of Racing and Hall of Fame. He was sired by Tale of Two Cities, a son of Tehran, winner of the 1944 St...

, and Riva Ridge.

Prove Out only won another stakes race, the 1974 Grey Lag Handicap

Grey Lag Handicap

The Grey Lag Handicap was an American Thoroughbred horse race run annually at Aqueduct Racetrack in Queens, New York. Open to horses age three and older, in itss final years it was contested on dirt over a distance of one and three-sixteenths miles .Inaugurated on May 10, 1941 at the Jamaica...

, and was later retired to stud. He was the broodmare sire of the champion filly Miesque

Miesque

Miesque was a champion Thoroughbred racemare, best known as the first horse to win two consecutive Breeders' Cups and racing awards in Europe and America. She was a Group one winner at two, three and four-years-old, for a total of 10 G1 wins. She produced five stakes winners.-Breeding:Miesque was...

.