n the stretch, Secretariat opened a 1/16 mile lead on the rest of the field. At the finish, he won by 31 lengths (breaking the margin-of-victory record set by Triple Crown winner Count Fleet in 1943, who won by 25 lengths), and ran the fastest 1½ miles on dirt in history, 2:24 flat, which broke the stakes record by more than two seconds.[SUP][20][/SUP][SUP][21][/SUP] This works out to a speed of 37.5 mph for his entire performance. Secretariat's record still stands; no other horse has ever broken 2:25 for 1½ miles on dirt. If the Beyer Speed Figure calculation had been developed during that time, Andrew Beyer calculated that Secretariat would have earned a figure of 139, the highest he has ever assigned.[SUP][22][/SUP] Bettors holding 5,617 winning parimutuel tickets on Secretariat never redeemed them, presumably keeping them as souvenirs (and because the tickets would have paid only $2.20 on a $2 bet).[SUP][23][/SUP] Secretariat became the ninth Triple Crown winner in history, and the first in 25 years.
[h=2]After the Triple Crown[/h] Three weeks after his win at Belmont, Secretariat shipped to Chicago and easily won the Arlington Invitational at Arlington Park. He went to Saratoga, popularly nicknamed "the graveyard of favorites," for the Whitney Stakes. Racing against older horses for the first time, he was beaten by the Allen Jerkens-trained Onion, a four-year-old gelding. Onion led from the start and led Secretariat by a head on the final turn before pulling ahead in the straight to win by a length. A record crowd of more than 30,000 witnessed what was described as an "astonishing" upset.[SUP][24][/SUP] Despite Jerkens's reputation as the "Giant Killer," Secretariat's stunning loss can possibly be attributed to a viral infection, which caused a low-grade fever and diarrhea.[SUP][25][/SUP]
Secretariat then won the inaugural Marlboro Cup against a field that included his stablemate, the 1972 Derby and Belmont Stakes winner Riva Ridge; top California stakes winner Cougar II, Canadian champion Kennedy Road, Onion, Travers winner Annihilate 'Em, and the 1972 American champion three-year-old male horse Key to the Mint. Secretariat ran 1:45[SUP]2[/SUP]⁄[SUB]5[/SUB] for 1[SUP]1[/SUP]⁄[SUB]8[/SUB] miles, then a world record for the distance. Stablemate Riva Ridge ran second.[SUP][26][/SUP]