Luciano Spalletti's Zenit remain five points clear at the top of the table after their 2-1 win at relegation-threatened Ural on Saturday.
They were made to work hard for their triumph though, with Ural - who have won just one match this season - taking advantage of Hulk's early miss from the penalty spot.
Shirokov's second came with 11 minutes remaining and gave Zenit their 11th win of the campaign.
Lokomotiv, who took the lead through Roman Pavlyuchenko, beat Rubin Kazan 2-1 on Sunday thanks to Dame N'Doye's late winner with just six minutes remaining.
Meanwhile, fourth-placed CSKA bounced back from three successive losses with a 5-1 thrashing of Krasnodar on Sunday, a result that was inspired by Zoran Tosic's hat-trick.
All of Tosic's goals came in a first half that striker Seydou Doumbia also scored in and, although Pavel Mamaev netted a consolation for the losers just after the break, there was still time for CSKA to score again.
At the other end of the table, Anzhi's search for their first win continued as they were beaten 2-0 by Kuban Krasnodar on Monday.
And on Friday, Artem Danilenko's 75th-minute strike helped Volga to a 2-2 draw at Krylya Sovetov.
