After a runner-up finish in the women's team event and both a silver and bronze medal in the all-around, the Russians came up with a gold in the uneven bars competition.
Mustafina's routine was easily the best of the eight finalists and she earned a score of 16.133. Defending Olympic champion He Kexin of China was second with a score of 15.933 and Britain's Elizabeth Tweedle took the bronze with 15.916 points.
American Gabby Douglas, winner of the all-around gold medal last week, finished last among the eight finalists.
The other individual apparatus finals held Monday were won by Arthur Nabarrete Zanetti of Brazil and Hak Seon Yang of South Korea.
The Brazilian came out on top in the rings event, receiving a score of 15.900 as the last performer of the final.
Chen Yibing of China was next at 15.800 and Italian Matteo Morandi was third at 15.733.
Yang captured the men's vault gold medal with an effort rewarded with 16.533 points.
Denis Ablyazin, the bronze medalist on Sunday in the floor exercise competition, took silver in the vault with a 16.399. Igor Radivilov of Ukraine was third with 16.316.
American Samuel Mikulak was fifth, leaving the Americans with only one medal to date in the apparatus finals. McKayla Maroney of the United States won a silver in the women's vault on Sunday. Four more finals will be held Tuesday.
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