- 1940: Niagara District A.A.U. champion. Before turning professional Claus beat Henry Brimm in two out of three fights.
- 1940: made the final of the New York Golden Gloves Tournanent of Champions and represented New York at the Intercity Golden Gloves Tournament.
- Fought three World Champions Tippy Larkin, Tony Zale and Rocky Graziano.
- 1949: retired after his bout with Rocky Graziano, having been paid a $3000 purse, the largest of his career, and began training and racing horses at Batavia Downs and Buffalo Raceway.