April 1966 saw Cardigan Bay sweep all three legs of the International Pacing Series, the International Pace, Good Time Pace and National Championship Pace at Yonkers Raceway. It was the first time a horse had won all three legs. Perhaps his most famous encounter was with the great Standardbred horse, Bret Hanover, in the Pace of the Century, in 1966. Cardigan Bay, with Stanley Dancer driving, won that race in front of 45,000 spectators at Yonkers Raceway and became only one of two horses (the other being Adios Vic) up to that time to have beaten Bret Hanover. However, in their next encounter at Roosevelt Raceway, the "Revenge Pace," Bret Hanover reversed that result with Cardigan Bay third before a crowd of 37,000.