Graabak took gold after finishing the ski phase in 23 minutes 27.5 seconds, 0.6 seconds ahead of competriot Moan, as Germany’s Fabian Riessle took bronze.
Riessle’s fellow German, Eric Frenzel, who won gold on the normal hill, led the field after the ski jumping phase to earn pole position for the decisive cross-country ski, which took the form of a first-past-the-post pursuit.
However he could not maintain the pace, and slipped back to finish 10th overall, as the Norwegians relentlessly closed the gap to move into the lead.
Both jumping and skiing phases took place in rainy and overcast conditions that the Norwegians claimed reminded them of their home base of Trondheim, on the coast in central Norway.
“We're a bit used to this kind of weather in Trondheim - rain, a bit grey,” said Graabak.
“We were discussing this in the car on the way to the arena today, saying that it was a bit like home, and I guess we took advantage of that,” he added.
Moan expanded on the topic: “Trondheim is on the coast in Norway and we are used to training in a lot of rain, so this was like a little bonus for us.”
And the silver medallist expressed great satisfaction with the quality of the ski jump and the cross-country skiing tracks at the RusSki Gorski Jumping Centre.
“Big respect to the organisation that made this possible,” he said. “It was fun to jump and ski today.”
The one-two for Graabak and Moan capped a brilliant day for Norwegian athletes in the Nordic disciplines, following Emil Hegle Svendsen’s triumph in the men’s biathlon 15km mass start