Belousova and Protopopov debuted at the World Championships in 1958, finishing 13th. They competed at their first Olympics two years later, placing ninth. In 1962, they made the World Championship podium for the first time, earning the silver medal. They were the first pair from the Soviet Union or Russia to win a world medal after the introduction of the pair skating discipline at the 1908 World Championships (in which only three pairs competed). Later in 1962, they won silver at the European Championships, becoming the second Soviet pair to win medals after Nina Zhuk / Stanislav Zhuk (who won silver in 1958, 1959, and 1960).