Jansrud, 32, swept down the piste in 1min 33.21sec at his home event to see off Switzerland’s Beat Feuz by 0.22s with France’s Brice Roger a further 0.11s back in third.
Roger, starting in 49th position, shaded Norway’s drien Smiseth Sejersted for third by one hundredths of a second.
Ahead of next week’s World Cup finals in Are, Sweden, Jansrud, on 360 points, is uncatchable in the Super-G standings after his closest pursuer, compatriot Aksel Lund Svindal, failed to finish on Sunday.
Jansrud took silver behind Svindal in the downhill at last month’s Pyeongchang Olympics where he also claimed bronze in the Super-G.
He was winning his 11th World Cup Super-G and second of the season after Lake Louise. He took the discipline’s crystal globe in 2015 and 2017.