The injury-plagued skier charged down the 3.3 kilometer Kandahar course in one minute 55.39 seconds, 0.18 seconds ahead of Austrian Vincent Kriechmayr and Italian Dominik Paris who tied for second place.
Norway's Aksel Lund Svindal, another of the favourites for Pyeongchang, was fourth in the last downhill race before the Games.
After missing the Vancouver Games through injury and failing to win a medal in Sochi, where he had still not fully recovered from a knee injury, Feuz this time appears to have hit form just at the right time.
Feuz, skiing fifth, was well outside Svindal's time at the halfway mark but picked up time as he threw caution to the wind near the end.
Feuz, who claimed the 10th World Cup win of his career, previously won this season at Lake Louise and Wengen.
He was also second in Beaver Creek and Kitzbuehel and leads the World Cup downhill standings with 542 points, 40 ahead of Svindal with Paris third.
Austrian slalom specialist Marcel Hirscher leads the overall standings ahead of Henrik Kristoffersen with Svindal third and Feuz fifth.
(Writing by Brian Homewood in Bern, editing by Pritha Sarkar)
