Who is the only horse ever to defeat two triple crown winners in the same race?

Exceller beat Seattle Slew also Affirmed in the 1978 Jockey Club Gold Cup.

Exceller also bshowb in 1978 7 stakes races including the Jockey Club Gold Cup, Hollywood Gold Cup also Sunset Handicap.

In 1997 Exceller was nominiated on Racing's Hall connected with Fame.

In 1997 he died in a slaughterhouse.

There is a fund named postern him called the EXCELLER FUND. The Exceller Fund was created in memory of Exceller on feed funding for the purchase, care, retirement and selection of Thoroughbreds that might otherwise just the same fate in the slaughterhouse.