The rigging was still there, of course, it's just that the loss was so big it couldn't be thoroughly disguised:
Western Monitors Criticize Russian Elections
MOSCOW — Western election monitors said on Monday that they had observed blatant fraud, including the brazen stuffing of ballot boxes, in the parliamentary elections that delivered surprisingly big losses to United Russia, the party led by Prime Minister Vladimir V. Putin.
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Petros Efthymiou, who led the short-term O.S.C.E. observer mission, said the elections “proved that the Russian people can form the future of this country by expressing their will despite many obstacles.” “However, changes are needed for the will of the people to be respected,” Mr. Efthymiou said. “I particularly noticed the interference of the state in all levels of political life, the lack of necessary conditions for fair competition and no independence of the media.”
Ambassador Heidi Tagliavini, who headed the mission of the O.S.C.E.’s Office for Democratic Institutions and Human Rights, compared the elections to “a game in which only some players are allowed on the pitch, and then the field is tilted in favor of one of the players.”
MORE:
http://www.nytimes.com/2011/12/06/world/europe/russian-parliamentary-elections-criticized-by-west.html?_r=1&hp