In 1930, Berg defeated the great Cuban fighter Kid Chocolate in ten rounds. The Chocolate bout, fought in Queens, New York in 1932, had 10,000 spectators, larger than many of his British bouts. In 1930, he knocked out the American champion Mushy Callahan to take the World Light Welterweight Championship in London. The National Boxing Association (NBA) had stripped Callahan before this fight and Britain did not recognize this division, so only the New York State Athletic Commission recognized Berg as champion after this fight. The NBA only recognized Berg as champion after he beat Goldie Hess in January 1931.