While neighbours Norway sit top of the table with a day to go, it hasn't been such a successful Games for the Finns, who started Saturday with a haul of four bronze medals.
But Niskanen attacked early -- less than 20km into the race -- and held off the competition to win by 18.7sec from Russians Alexander Bolshunov and Andrey Larkov.
\"I wanted to win a gold medal over this distance and it has been a long four years," said the Sochi 2014 team sprint gold medallist.
"But I handled the pressure and everything went perfectly today so that's the result now."
Finland's Krista Parmakoski already has two bronze medals at this Games, while Enni Rukajarvi was third in the women's slopestyle and the Finnish women were bronze-medallists in the ice hockey.