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.