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. Berg fought as a lightweight when he put his title on the line to meet with Tony Canzoneri in Chicago on 24 April 1931. He was quickly knocked out in three rounds, falling on his face and stumbling to get up before giving in and collapsing into the ropes. Berg, contending that he lost at lightweight and not at light welterweight, continued to claim that he was champion. Most of the boxing world recognized Canzoneri, however. He unsuccessfully challenged Canzoneri again for the title in September 1931. After the Canzoneri bout, Berg continued boxing with mixed results. He became British lightweight champion in 1934 by beating the title holder Harry Mizler, another Jewish boxer. He was thrust back into the limelight as a replacement for the injured Canzoneri against Cleto Locatelli at Madison Square Garden, but his hopes of challenging for the world title faded after a points defeat to Gustave Humery in Paris in February 1935, also losing a return bout in London in April, although Berg was still British champion at this point. Later that year he lost to Laurie Stevens in a fight for the British Empire lightweight title in Johannesburg. He returned to fighting at welterweight in the United States with some success. In August 1936, after three straight defeats, he announced his retirement, but returned in January 1937 with a victory against Ivor Pickens, the first of a nine fight unbeaten run. In January 1941 he moved up to middleweight to fight Harry Craster. He again beat Mizler in February 1941 and defeated British lightweight champion Eric Boon on a disqualification due to a low blow in a non-title fight in April 1941. After a victory over Eric Dolby in March 1945, Berg expressed a desire to once more challenge for a title, saying "What I need is fights. I'm a bad gymnasium worker, but I'll show what I can do in the ring. When I've had a few warm up fights I'll know where I stand. If I'm no good I'll quit." He had two further fights, the last a win by knockout against Johnny MacDonald in May