The Fortec Motorsports driver from the Netherlands made a clean start from pole, leading from Marco Sorensen (Lotus) and Jules Bianchi (Tech 1 racing), who resisted early challenges from ISR’s Sam Bird and Arthur Pic (Dams).
That five-man group soon pulled away from the pack, with Frijns and Sorensen themselves opening up a six-second gap by the 10-minute mark.
Sorensen paid a heavy price for his attempts to stay with Frijns, though, spinning off and falling to the back of the leading pack.
The safety car made a couple of appearances later in the race, with Frijns a comfortable winner from Bianchi and Bird in the end, the Dutchman moving 10 points clear of Bird atop the standings.
It capped off a good day for Frijns, who had earlier test-driven a Red Bull demo, the first Formula One car to appear on the Moscow Raceway.