The two-time Olympian was looking to bounce back from a disappointing halfpipe World Cup opener in New Zealand back in August.
And he did exactly that as he scored a blistering 89.00 points in a blistering first run to secure top spot.
There was more for the home crowd to celebrate as compatriot Markus Malin placed third, with Frenchman Johann Baisamy sandwiched in between in second – with Great Britain’s Dominic Harrington finishing 26th.
The victory means Korpi catapults himself to the top of the halfpipe World Cup standing on 1020 points, 20 ahead of Japan’s Ayumu Hirano who was not competing in Ruka, while Baisamy sits third on 930.
In the women's event China's Shuang Li scored 85.75 points for the victory, with New Zealander Rebecca Sinclair second with 83.75 and France’s Clemence Grimal in third.
Li now leads the overall standings on 1260 points, pushing the winner of the opening World Cup event Kelly Clark of America down to second while Sinclair is third.