Complex sentence: As a professional badminton player, however, Purcell beat all the leading players in the world by 1932-was declared world champion in 1933 based on his record against leading Canadian, American and British badminton players.
Split into simpler sentences: As a professional badminton player, however, Purcell beat all the leading players in the world by 1932. He was declared world champion in 1933 based on his beating the top Canadian, American and British badminton players.