Sam added Spa Francorchamps to his 2013 CV of success with a pole position and victory that keep him right in the hunt for the championship.
The victory at the circuit makes the RUSSIAN TIME racer the only four-time winner so far this GP2 season, adding another historic circuit to a tally that also includes wins at Silverstone and Monaco.
And, just as with his three previous victories, the Mercedes AMG Petronas development and reserve driver also had the satisfaction of seeing one of his F1 colleagues take pole position in the main event.
Sam had been expected to face pressure early in the race from rivals using different tyre strategies, but he defended his lead away from the line, then calmly managed the re-start after a safety car period.
This left him able to build an advantage that lasted through the pitstop and onwards to a seven-second victory - his third feature race win of the year.
He said: "I had a bit of a twitch going through Eau Rouge first time which enabled Calado to have a little sniff going into Turn 5, but after that it was fairly plain sailing.
"It was a really great job from RUSSIAN TIME because the car they gave me was very, very good. It was just a matter of controlling the speed with the last ten laps."
Although his sprint race was blighted by an engine misfire, he was still able to comfortably out-score his three main championship rivals over the weekend, setting up a potentially thrilling climax to the GP2 title fight.
He said: "We'll see what happens in the next races, but for sure it’s close. I think up to the last round of the championship, the positions you see right now will not be the positions you see then. We’re within touching distance, and there are also people behind making moves forward as well."
Sam will return to action at Monza on the weekend of September 6-8.