CSKA had the chance to move ahead of Rostov at the top of the table by beating Zenit but, instead, it was the reigning league champions who took the initiative by winning their third successive game.
Zenit moved into fourth place, just a point behind Lokomotiv Moscow, three behind CSKA and four adrift of Rostov after they dominated Sunday's top-of-the-table contest with Hulk providing the cutting edge for them.
Zenit had to wait until the 54th minute to break the deadlock with Artem Dzyuba playing in Hulk, who struck a fierce shot into the far corner.
With 11 minutes left, the Brazilian then curled in a free kick that found its way past CSKA goalkeeper Igor Akinfeev with the help of a deflection.
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"We haven't won three matches in a row for a long time," said Zenit head coach Andre Villas-Boas.
"We need to continue this winning run and continue to keep on playing like we did today."
With eight matches remaining, Rostov are still in the driving seat after beating Spartak Moscow 2-0 on Saturday.
(Reporting By Dmitriy Rogovitskiy, editing by Ian Chadband)
