World champions Anastasia Davydova and Anastasia Yermakova scored eight perfect 10s as they claimed gold in the synchronised swimming duet.
The Russians led all three rounds to push Japan's Miya Tachibana and Miho Takeda into second, as they did in 2000 and at last year's world championships.
The Russians scored 99.334 points with the Japanese achieving 98.417.
The American pair of Alison Bartosik and Anna Kozlova took bronze after the free routine final with 96.918.
It is the second straight duet title for Russia after Olga
Brusnikina and Maria Kisseleva won for the first time in Sydney four years ago.
Spanish pair Gemma Mengual and Paola Tirados hit out at the judges after finishing fourth.
"We're very angry because Spain has made huge progress in synchronised swimming. The score is a matter of politics," complained 27-year-old Mengual.
"We think that on the podium there must be a duet from Asia, one from America and one from Europe according to the traditional politics of the sport."
Tirados added: "Everything went well. We had only a few
technical errors, but the score was less than we expected, especially in the artistic side."